bug#32773: clang: missing default include paths for C++

bug#32773: clang: missing default include paths for C++

[Tim Gesthuizen]

Hi,
I noticed the following bug in clang when installed through guix:
Compiling C++ programs does not work because the include path is not set
correctly.

I will use the following test program for compling:

┌────
│ #include <iostream>
│
│ int
│ main()
│ {
│     std::cout << "Hello, World\n";
│ }
└────

When I now compile using clang I get the following error message:

┌────
│ which clang++
│ clang++ test.cc 2>&1
│ exit 0
└────

┌────
│ /home/tibbe/.guix-profile/bin/clang++
│ test.cc:1:10: fatal error: 'iostream' file not found
│ #include <iostream>
│ 	 ^~~~~~~~~~
│ 1 error generated.
└────

┌────
│ which g++
│ g++ test.cc 2>&1
│ exit 0
└────

┌────
│ /home/tibbe/.guix-profile/bin/g++
└────

As you can see g++ has no problem compiling the code, but clang++ cannot
find the `<iostream>' header. This is due to the already mentioned bad
include paths:

┌────
│ g++ -v test.cc 2>&1
│ clang++ -v test.cc 2>&1
│ exit 0
└────

┌────
│ Using built-in specs.
│ COLLECT_GCC=g++
│
COLLECT_LTO_WRAPPER=/gnu/store/758qfjvn4wnsrhrr08pmwfr77vmcq4q2-gcc-8.2.0/libexec/gcc/x86_64-unknown-linux-gnu/8.2.0/lto-wrapper
│ Target: x86_64-unknown-linux-gnu
│ Configured with:
│ Thread model: posix
│ gcc version 8.2.0 (GCC)
│ COLLECT_GCC_OPTIONS='-v' '-shared-libgcc' '-mtune=generic' '-march=x86-64'
│
/gnu/store/758qfjvn4wnsrhrr08pmwfr77vmcq4q2-gcc-8.2.0/libexec/gcc/x86_64-unknown-linux-gnu/8.2.0/cc1plus
-quiet -v -D_GNU_SOURCE test.cc -quiet -dumpbase test.cc -mtune=generic
-march=x86-64 -auxbase test -version -o /tmp/cceSqDtK.s
│ GNU C++14 (GCC) version 8.2.0 (x86_64-unknown-linux-gnu)
│ 	compiled by GNU C version 8.2.0, GMP version 6.1.2, MPFR version
4.0.1, MPC version 1.1.0, isl version isl-0.18-GMP
│
│ GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
│ ignoring nonexistent directory "/no-gcc-local-prefix/include"
│ ignoring nonexistent directory
"/gnu/store/bmaxmigwnlbdpls20px2ipq1fll36ncd-gcc-8.2.0-lib/lib/gcc/x86_64-unknown-linux-gnu/8.2.0/../../../../../../../x86_64-unknown-linux-gnu/include"
│ #include "..." search starts here:
│ #include <...> search starts here:
│  /home/tibbe/.guix-profile/include
│  /gnu/store/758qfjvn4wnsrhrr08pmwfr77vmcq4q2-gcc-8.2.0/include/c++
│
/gnu/store/758qfjvn4wnsrhrr08pmwfr77vmcq4q2-gcc-8.2.0/include/c++/x86_64-unknown-linux-gnu
│
/gnu/store/758qfjvn4wnsrhrr08pmwfr77vmcq4q2-gcc-8.2.0/include/c++/backward
│
/gnu/store/bmaxmigwnlbdpls20px2ipq1fll36ncd-gcc-8.2.0-lib/lib/gcc/x86_64-unknown-linux-gnu/8.2.0/include
│
/gnu/store/bmaxmigwnlbdpls20px2ipq1fll36ncd-gcc-8.2.0-lib/lib/gcc/x86_64-unknown-linux-gnu/8.2.0/include-fixed
│  /gnu/store/l4lr0f5cjd0nbsaaf8b5dmcw1a1yypr3-glibc-2.27/include
│ End of search list.
│ GNU C++14 (GCC) version 8.2.0 (x86_64-unknown-linux-gnu)
│ 	compiled by GNU C version 8.2.0, GMP version 6.1.2, MPFR version
4.0.1, MPC version 1.1.0, isl version isl-0.18-GMP
│
│ GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
│ Compiler executable checksum: 238b7d99644945f4ccaa2a89b02dcd25
│ COLLECT_GCC_OPTIONS='-v' '-shared-libgcc' '-mtune=generic' '-march=x86-64'
│  as -v --64 -o /tmp/ccZKb9XQ.o /tmp/cceSqDtK.s
│ GNU assembler version 2.30 (x86_64-unknown-linux-gnu) using BFD
version (GNU Binutils) 2.30
│
COMPILER_PATH=/gnu/store/758qfjvn4wnsrhrr08pmwfr77vmcq4q2-gcc-8.2.0/libexec/gcc/x86_64-unknown-linux-gnu/8.2.0/:/gnu/store/758qfjvn4wnsrhrr08pmwfr77vmcq4q2-gcc-8.2.0/libexec/gcc/x86_64-unknown-linux-gnu/8.2.0/:/gnu/store/758qfjvn4wnsrhrr08pmwfr77vmcq4q2-gcc-8.2.0/libexec/gcc/x86_64-unknown-linux-gnu/:/gnu/store/bmaxmigwnlbdpls20px2ipq1fll36ncd-gcc-8.2.0-lib/lib/gcc/x86_64-unknown-linux-gnu/8.2.0/:/gnu/store/bmaxmigwnlbdpls20px2ipq1fll36ncd-gcc-8.2.0-lib/lib/gcc/x86_64-unknown-linux-gnu/
│
LIBRARY_PATH=/home/tibbe/.guix-profile/lib/:/home/tibbe/.guix-profile/lib/:/gnu/store/bmaxmigwnlbdpls20px2ipq1fll36ncd-gcc-8.2.0-lib/lib/gcc/x86_64-unknown-linux-gnu/8.2.0/:/gnu/store/bmaxmigwnlbdpls20px2ipq1fll36ncd-gcc-8.2.0-lib/lib/gcc/x86_64-unknown-linux-gnu/8.2.0/../../../:/gnu/store/l4lr0f5cjd0nbsaaf8b5dmcw1a1yypr3-glibc-2.27/lib
│ COLLECT_GCC_OPTIONS='-v' '-shared-libgcc' '-mtune=generic' '-march=x86-64'
│
/gnu/store/758qfjvn4wnsrhrr08pmwfr77vmcq4q2-gcc-8.2.0/libexec/gcc/x86_64-unknown-linux-gnu/8.2.0/collect2
-plugin
/gnu/store/758qfjvn4wnsrhrr08pmwfr77vmcq4q2-gcc-8.2.0/libexec/gcc/x86_64-unknown-linux-gnu/8.2.0/liblto_plugin.so
-plugin-opt=/gnu/store/758qfjvn4wnsrhrr08pmwfr77vmcq4q2-gcc-8.2.0/libexec/gcc/x86_64-unknown-linux-gnu/8.2.0/lto-wrapper
-plugin-opt=-fresolution=/tmp/ccKNZuuX.res
-plugin-opt=-pass-through=-lgcc_s -plugin-opt=-pass-through=-lgcc
-plugin-opt=-pass-through=-lgcc_s -plugin-opt=-pass-through=-lc
-plugin-opt=-pass-through=-lgcc_s -plugin-opt=-pass-through=-lgcc
--eh-frame-hdr -m elf_x86_64 -dynamic-linker
/gnu/store/l4lr0f5cjd0nbsaaf8b5dmcw1a1yypr3-glibc-2.27/lib/ld-linux-x86-64.so.2
/home/tibbe/.guix-profile/lib/crt1.o
/home/tibbe/.guix-profile/lib/crti.o
/gnu/store/bmaxmigwnlbdpls20px2ipq1fll36ncd-gcc-8.2.0-lib/lib/gcc/x86_64-unknown-linux-gnu/8.2.0/crtbegin.o
-L/home/tibbe/.guix-profile/lib -L/home/tibbe/.guix-profile/lib
-L/gnu/store/bmaxmigwnlbdpls20px2ipq1fll36ncd-gcc-8.2.0-lib/lib/gcc/x86_64-unknown-linux-gnu/8.2.0
-L/gnu/store/bmaxmigwnlbdpls20px2ipq1fll36ncd-gcc-8.2.0-lib/lib/gcc/x86_64-unknown-linux-gnu/8.2.0/../../..
-L/gnu/store/l4lr0f5cjd0nbsaaf8b5dmcw1a1yypr3-glibc-2.27/lib
/tmp/ccZKb9XQ.o -lstdc++ -lm -lgcc_s -lgcc
-L/gnu/store/l4lr0f5cjd0nbsaaf8b5dmcw1a1yypr3-glibc-2.27/lib
-rpath=/gnu/store/l4lr0f5cjd0nbsaaf8b5dmcw1a1yypr3-glibc-2.27/lib
-rpath=/gnu/store/bmaxmigwnlbdpls20px2ipq1fll36ncd-gcc-8.2.0-lib/lib
-lgcc_s -lc -lgcc_s -lgcc
/gnu/store/bmaxmigwnlbdpls20px2ipq1fll36ncd-gcc-8.2.0-lib/lib/gcc/x86_64-unknown-linux-gnu/8.2.0/crtend.o
/home/tibbe/.guix-profile/lib/crtn.o
│ COLLECT_GCC_OPTIONS='-v' '-shared-libgcc' '-mtune=generic' '-march=x86-64'
│ clang version 6.0.0 (tags/RELEASE_600/final)
│ Target: x86_64-unknown-linux-gnu
│ Thread model: posix
│ InstalledDir: /home/tibbe/.guix-profile/bin
│ Found candidate GCC installation:
/gnu/store/bgc2ckrkyz5fg4sp278msyzxs5a30pwa-gcc-5.5.0-lib/lib/gcc/x86_64-unknown-linux-gnu/5.5.0
│ Selected GCC installation:
/gnu/store/bgc2ckrkyz5fg4sp278msyzxs5a30pwa-gcc-5.5.0-lib/lib/gcc/x86_64-unknown-linux-gnu/5.5.0
│ Candidate multilib: .;@m64
│ Selected multilib: .;@m64
│
"/gnu/store/dy7lcm3d0dbh4510vkc0dv35g48pis50-clang-6.0.0/bin/clang-6.0"
-cc1 -triple x86_64-unknown-linux-gnu -emit-obj -mrelax-all
-disable-free -disable-llvm-verifier -discard-value-names
-main-file-name test.cc -mrelocation-model static -mthread-model posix
-mdisable-fp-elim -fmath-errno -masm-verbose -mconstructor-aliases
-munwind-tables -fuse-init-array -target-cpu x86-64 -dwarf-column-info
-debugger-tuning=gdb -v -resource-dir
/gnu/store/dy7lcm3d0dbh4510vkc0dv35g48pis50-clang-6.0.0/lib/clang/6.0.0
-I/home/tibbe/.guix-profile/include -internal-isystem /usr/local/include
-internal-isystem
/gnu/store/dy7lcm3d0dbh4510vkc0dv35g48pis50-clang-6.0.0/lib/clang/6.0.0/include
-internal-externc-isystem
/gnu/store/l4lr0f5cjd0nbsaaf8b5dmcw1a1yypr3-glibc-2.27/include
-fdeprecated-macro -fdebug-compilation-dir /home/tibbe/src/hello-world
-ferror-limit 19 -fmessage-length 0 -fobjc-runtime=gcc -fcxx-exceptions
-fexceptions -fdiagnostics-show-option -o /tmp/test-b83cb1.o -x c++ test.cc
│ clang -cc1 version 6.0.0 based upon LLVM 6.0.0 default target
x86_64-unknown-linux-gnu
│ #include "..." search starts here:
│ #include <...> search starts here:
│  /home/tibbe/.guix-profile/include
│  /usr/local/include
│
/gnu/store/dy7lcm3d0dbh4510vkc0dv35g48pis50-clang-6.0.0/lib/clang/6.0.0/include
│  /gnu/store/l4lr0f5cjd0nbsaaf8b5dmcw1a1yypr3-glibc-2.27/include
│ End of search list.
│ test.cc:1:10: fatal error: 'iostream' file not found
│ #include <iostream>
│ 	 ^~~~~~~~~~
│ 1 error generated.
└────

As you can see from the output, clang is missing some include paths that
gcc has. Specifying a custom `CPLUS_INCLUDE_PATH' fixes the problem:

┌────
│
CPLUS_INCLUDE_PATH=$HOME/.guix-profile/include/c++:$HOME/.guix-profile/include/c++/x86_64-unknown-linux-gnu/
clang++ test.cc
│ ./a.out
└────

┌────
│ Hello, World
└────

This is already done in the package definition for the
`C_INCLUDE_PATH'. It is not done for C++ because clang does not
implement a feature or build system variable for changing it.

Fixing this problem would probably include an upstream patch enabling a
similar feature for C++ for what is already done in C and configuring
this variable in build phase to add the same include paths that g++ has.

Tim.

bug#32773: clang: missing default include paths for C++

[Pjotr Prins]

Hi Tim,

I am not sure this helps but in a project I have I use 

  CPPFLAGS= -std=c++11 

and

  CPPFLAGS += -I$(GUIX)/include/c++ -I$(GUIX)/include/c++/x86_64-unknown-linux-gnu

to find include files in Guix context with clang. Where $(GUIX) is the
profile.

Similar to yours. Glad to hear of a better way.

On Wed, Sep 19, 2018 at 08:23:14PM +0200, Tim Gesthuizen wrote:
> Hi,
> I noticed the following bug in clang when installed through guix:
> Compiling C++ programs does not work because the include path is not set
> correctly.
> 
> I will use the following test program for compling:
> 
> ┌────
> │ #include <iostream>
> │
> │ int
> │ main()
> │ {
> │     std::cout << "Hello, World\n";
> │ }
> └────
> 
> When I now compile using clang I get the following error message:
> 
> ┌────
> │ which clang++
> │ clang++ test.cc 2>&1
> │ exit 0
> └────
> 
> ┌────
> │ /home/tibbe/.guix-profile/bin/clang++
> │ test.cc:1:10: fatal error: 'iostream' file not found
> │ #include <iostream>
> │ 	 ^~~~~~~~~~
> │ 1 error generated.
> └────
> 
> ┌────
> │ which g++
> │ g++ test.cc 2>&1
> │ exit 0
> └────
> 
> ┌────
> │ /home/tibbe/.guix-profile/bin/g++
> └────
> 
> As you can see g++ has no problem compiling the code, but clang++ cannot
> find the `<iostream>' header. This is due to the already mentioned bad
> include paths:
> 
> ┌────
> │ g++ -v test.cc 2>&1
> │ clang++ -v test.cc 2>&1
> │ exit 0
> └────
> 
> ┌────
> │ Using built-in specs.
> │ COLLECT_GCC=g++
> │
> COLLECT_LTO_WRAPPER=/gnu/store/758qfjvn4wnsrhrr08pmwfr77vmcq4q2-gcc-8.2.0/libexec/gcc/x86_64-unknown-linux-gnu/8.2.0/lto-wrapper
> │ Target: x86_64-unknown-linux-gnu
> │ Configured with:
> │ Thread model: posix
> │ gcc version 8.2.0 (GCC)
> │ COLLECT_GCC_OPTIONS='-v' '-shared-libgcc' '-mtune=generic' '-march=x86-64'
> │
> /gnu/store/758qfjvn4wnsrhrr08pmwfr77vmcq4q2-gcc-8.2.0/libexec/gcc/x86_64-unknown-linux-gnu/8.2.0/cc1plus
> -quiet -v -D_GNU_SOURCE test.cc -quiet -dumpbase test.cc -mtune=generic
> -march=x86-64 -auxbase test -version -o /tmp/cceSqDtK.s
> │ GNU C++14 (GCC) version 8.2.0 (x86_64-unknown-linux-gnu)
> │ 	compiled by GNU C version 8.2.0, GMP version 6.1.2, MPFR version
> 4.0.1, MPC version 1.1.0, isl version isl-0.18-GMP
> │
> │ GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
> │ ignoring nonexistent directory "/no-gcc-local-prefix/include"
> │ ignoring nonexistent directory
> "/gnu/store/bmaxmigwnlbdpls20px2ipq1fll36ncd-gcc-8.2.0-lib/lib/gcc/x86_64-unknown-linux-gnu/8.2.0/../../../../../../../x86_64-unknown-linux-gnu/include"
> │ #include "..." search starts here:
> │ #include <...> search starts here:
> │  /home/tibbe/.guix-profile/include
> │  /gnu/store/758qfjvn4wnsrhrr08pmwfr77vmcq4q2-gcc-8.2.0/include/c++
> │
> /gnu/store/758qfjvn4wnsrhrr08pmwfr77vmcq4q2-gcc-8.2.0/include/c++/x86_64-unknown-linux-gnu
> │
> /gnu/store/758qfjvn4wnsrhrr08pmwfr77vmcq4q2-gcc-8.2.0/include/c++/backward
> │
> /gnu/store/bmaxmigwnlbdpls20px2ipq1fll36ncd-gcc-8.2.0-lib/lib/gcc/x86_64-unknown-linux-gnu/8.2.0/include
> │
> /gnu/store/bmaxmigwnlbdpls20px2ipq1fll36ncd-gcc-8.2.0-lib/lib/gcc/x86_64-unknown-linux-gnu/8.2.0/include-fixed
> │  /gnu/store/l4lr0f5cjd0nbsaaf8b5dmcw1a1yypr3-glibc-2.27/include
> │ End of search list.
> │ GNU C++14 (GCC) version 8.2.0 (x86_64-unknown-linux-gnu)
> │ 	compiled by GNU C version 8.2.0, GMP version 6.1.2, MPFR version
> 4.0.1, MPC version 1.1.0, isl version isl-0.18-GMP
> │
> │ GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
> │ Compiler executable checksum: 238b7d99644945f4ccaa2a89b02dcd25
> │ COLLECT_GCC_OPTIONS='-v' '-shared-libgcc' '-mtune=generic' '-march=x86-64'
> │  as -v --64 -o /tmp/ccZKb9XQ.o /tmp/cceSqDtK.s
> │ GNU assembler version 2.30 (x86_64-unknown-linux-gnu) using BFD
> version (GNU Binutils) 2.30
> │
> COMPILER_PATH=/gnu/store/758qfjvn4wnsrhrr08pmwfr77vmcq4q2-gcc-8.2.0/libexec/gcc/x86_64-unknown-linux-gnu/8.2.0/:/gnu/store/758qfjvn4wnsrhrr08pmwfr77vmcq4q2-gcc-8.2.0/libexec/gcc/x86_64-unknown-linux-gnu/8.2.0/:/gnu/store/758qfjvn4wnsrhrr08pmwfr77vmcq4q2-gcc-8.2.0/libexec/gcc/x86_64-unknown-linux-gnu/:/gnu/store/bmaxmigwnlbdpls20px2ipq1fll36ncd-gcc-8.2.0-lib/lib/gcc/x86_64-unknown-linux-gnu/8.2.0/:/gnu/store/bmaxmigwnlbdpls20px2ipq1fll36ncd-gcc-8.2.0-lib/lib/gcc/x86_64-unknown-linux-gnu/
> │
> LIBRARY_PATH=/home/tibbe/.guix-profile/lib/:/home/tibbe/.guix-profile/lib/:/gnu/store/bmaxmigwnlbdpls20px2ipq1fll36ncd-gcc-8.2.0-lib/lib/gcc/x86_64-unknown-linux-gnu/8.2.0/:/gnu/store/bmaxmigwnlbdpls20px2ipq1fll36ncd-gcc-8.2.0-lib/lib/gcc/x86_64-unknown-linux-gnu/8.2.0/../../../:/gnu/store/l4lr0f5cjd0nbsaaf8b5dmcw1a1yypr3-glibc-2.27/lib
> │ COLLECT_GCC_OPTIONS='-v' '-shared-libgcc' '-mtune=generic' '-march=x86-64'
> │
> /gnu/store/758qfjvn4wnsrhrr08pmwfr77vmcq4q2-gcc-8.2.0/libexec/gcc/x86_64-unknown-linux-gnu/8.2.0/collect2
> -plugin
> /gnu/store/758qfjvn4wnsrhrr08pmwfr77vmcq4q2-gcc-8.2.0/libexec/gcc/x86_64-unknown-linux-gnu/8.2.0/liblto_plugin.so
> -plugin-opt=/gnu/store/758qfjvn4wnsrhrr08pmwfr77vmcq4q2-gcc-8.2.0/libexec/gcc/x86_64-unknown-linux-gnu/8.2.0/lto-wrapper
> -plugin-opt=-fresolution=/tmp/ccKNZuuX.res
> -plugin-opt=-pass-through=-lgcc_s -plugin-opt=-pass-through=-lgcc
> -plugin-opt=-pass-through=-lgcc_s -plugin-opt=-pass-through=-lc
> -plugin-opt=-pass-through=-lgcc_s -plugin-opt=-pass-through=-lgcc
> --eh-frame-hdr -m elf_x86_64 -dynamic-linker
> /gnu/store/l4lr0f5cjd0nbsaaf8b5dmcw1a1yypr3-glibc-2.27/lib/ld-linux-x86-64.so.2
> /home/tibbe/.guix-profile/lib/crt1.o
> /home/tibbe/.guix-profile/lib/crti.o
> /gnu/store/bmaxmigwnlbdpls20px2ipq1fll36ncd-gcc-8.2.0-lib/lib/gcc/x86_64-unknown-linux-gnu/8.2.0/crtbegin.o
> -L/home/tibbe/.guix-profile/lib -L/home/tibbe/.guix-profile/lib
> -L/gnu/store/bmaxmigwnlbdpls20px2ipq1fll36ncd-gcc-8.2.0-lib/lib/gcc/x86_64-unknown-linux-gnu/8.2.0
> -L/gnu/store/bmaxmigwnlbdpls20px2ipq1fll36ncd-gcc-8.2.0-lib/lib/gcc/x86_64-unknown-linux-gnu/8.2.0/../../..
> -L/gnu/store/l4lr0f5cjd0nbsaaf8b5dmcw1a1yypr3-glibc-2.27/lib
> /tmp/ccZKb9XQ.o -lstdc++ -lm -lgcc_s -lgcc
> -L/gnu/store/l4lr0f5cjd0nbsaaf8b5dmcw1a1yypr3-glibc-2.27/lib
> -rpath=/gnu/store/l4lr0f5cjd0nbsaaf8b5dmcw1a1yypr3-glibc-2.27/lib
> -rpath=/gnu/store/bmaxmigwnlbdpls20px2ipq1fll36ncd-gcc-8.2.0-lib/lib
> -lgcc_s -lc -lgcc_s -lgcc
> /gnu/store/bmaxmigwnlbdpls20px2ipq1fll36ncd-gcc-8.2.0-lib/lib/gcc/x86_64-unknown-linux-gnu/8.2.0/crtend.o
> /home/tibbe/.guix-profile/lib/crtn.o
> │ COLLECT_GCC_OPTIONS='-v' '-shared-libgcc' '-mtune=generic' '-march=x86-64'
> │ clang version 6.0.0 (tags/RELEASE_600/final)
> │ Target: x86_64-unknown-linux-gnu
> │ Thread model: posix
> │ InstalledDir: /home/tibbe/.guix-profile/bin
> │ Found candidate GCC installation:
> /gnu/store/bgc2ckrkyz5fg4sp278msyzxs5a30pwa-gcc-5.5.0-lib/lib/gcc/x86_64-unknown-linux-gnu/5.5.0
> │ Selected GCC installation:
> /gnu/store/bgc2ckrkyz5fg4sp278msyzxs5a30pwa-gcc-5.5.0-lib/lib/gcc/x86_64-unknown-linux-gnu/5.5.0
> │ Candidate multilib: .;@m64
> │ Selected multilib: .;@m64
> │
> "/gnu/store/dy7lcm3d0dbh4510vkc0dv35g48pis50-clang-6.0.0/bin/clang-6.0"
> -cc1 -triple x86_64-unknown-linux-gnu -emit-obj -mrelax-all
> -disable-free -disable-llvm-verifier -discard-value-names
> -main-file-name test.cc -mrelocation-model static -mthread-model posix
> -mdisable-fp-elim -fmath-errno -masm-verbose -mconstructor-aliases
> -munwind-tables -fuse-init-array -target-cpu x86-64 -dwarf-column-info
> -debugger-tuning=gdb -v -resource-dir
> /gnu/store/dy7lcm3d0dbh4510vkc0dv35g48pis50-clang-6.0.0/lib/clang/6.0.0
> -I/home/tibbe/.guix-profile/include -internal-isystem /usr/local/include
> -internal-isystem
> /gnu/store/dy7lcm3d0dbh4510vkc0dv35g48pis50-clang-6.0.0/lib/clang/6.0.0/include
> -internal-externc-isystem
> /gnu/store/l4lr0f5cjd0nbsaaf8b5dmcw1a1yypr3-glibc-2.27/include
> -fdeprecated-macro -fdebug-compilation-dir /home/tibbe/src/hello-world
> -ferror-limit 19 -fmessage-length 0 -fobjc-runtime=gcc -fcxx-exceptions
> -fexceptions -fdiagnostics-show-option -o /tmp/test-b83cb1.o -x c++ test.cc
> │ clang -cc1 version 6.0.0 based upon LLVM 6.0.0 default target
> x86_64-unknown-linux-gnu
> │ #include "..." search starts here:
> │ #include <...> search starts here:
> │  /home/tibbe/.guix-profile/include
> │  /usr/local/include
> │
> /gnu/store/dy7lcm3d0dbh4510vkc0dv35g48pis50-clang-6.0.0/lib/clang/6.0.0/include
> │  /gnu/store/l4lr0f5cjd0nbsaaf8b5dmcw1a1yypr3-glibc-2.27/include
> │ End of search list.
> │ test.cc:1:10: fatal error: 'iostream' file not found
> │ #include <iostream>
> │ 	 ^~~~~~~~~~
> │ 1 error generated.
> └────
> 
> As you can see from the output, clang is missing some include paths that
> gcc has. Specifying a custom `CPLUS_INCLUDE_PATH' fixes the problem:
> 
> ┌────
> │
> CPLUS_INCLUDE_PATH=$HOME/.guix-profile/include/c++:$HOME/.guix-profile/include/c++/x86_64-unknown-linux-gnu/
> clang++ test.cc
> │ ./a.out
> └────
> 
> ┌────
> │ Hello, World
> └────
> 
> This is already done in the package definition for the
> `C_INCLUDE_PATH'. It is not done for C++ because clang does not
> implement a feature or build system variable for changing it.
> 
> Fixing this problem would probably include an upstream patch enabling a
> similar feature for C++ for what is already done in C and configuring
> this variable in build phase to add the same include paths that g++ has.
> 
> Tim.
> 
> 
> 

bug#32773: clang: missing default include paths for C++

[Tim Gesthuizen]

On 19.09.2018 20:33, Pjotr Prins wrote:
> Hi Tim,
> 
> I am not sure this helps but in a project I have I use 
> 
>   CPPFLAGS= -std=c++11 
> 
> and
> 
>   CPPFLAGS += -I$(GUIX)/include/c++ -I$(GUIX)/include/c++/x86_64-unknown-linux-gnu
> 
> to find include files in Guix context with clang. Where $(GUIX) is the
> profile.
> 
> Similar to yours. Glad to hear of a better way.

Yes, that seems to be quite the same to my workaround.
Its just that this is  a workaround that is difficult to get working in
some contexts: I want to use emacs-irony-mode through guix which is not
really useable because it won't autocomplete any std::* stuff.
If you take all packages that might want to use libclang and other
features of clang it might be a better solution to find a proper fix for
this problem. Also both workarounds need a user profile that is
cluttered with all include files.
I had a quick look into clangs source code how C_INCLUDE_DIRS is
implemented. It should be more or less easy to add the same option for
C++ (even C_INCLUDE_DIRS seems to be tinkered in to me).
I just wanted to file a bug about this because fixing this is not
trivial and I am not sure whether I will find the time right away to fix it.
Fixing it would also have the benefit that I could send the patch to the
LLVM mailing list and we might see the change upstream in the next LLVM
version.

Tim.

bug#32773: clang: missing default include paths for C++

[fis trivial]

Tim Gesthuizen writes:

> On 19.09.2018 20:33, Pjotr Prins wrote:
>> Hi Tim,
>>
>> I am not sure this helps but in a project I have I use
>>
>>   CPPFLAGS= -std=c++11
>>
>> and
>>
>>   CPPFLAGS += -I$(GUIX)/include/c++ -I$(GUIX)/include/c++/x86_64-unknown-linux-gnu
>>
>> to find include files in Guix context with clang. Where $(GUIX) is the
>> profile.
>>
>> Similar to yours. Glad to hear of a better way.
>
> Yes, that seems to be quite the same to my workaround.
> Its just that this is  a workaround that is difficult to get working in
> some contexts: I want to use emacs-irony-mode through guix which is not
> really useable because it won't autocomplete any std::* stuff.
> If you take all packages that might want to use libclang and other
> features of clang it might be a better solution to find a proper fix for
> this problem. Also both workarounds need a user profile that is
> cluttered with all include files.
> I had a quick look into clangs source code how C_INCLUDE_DIRS is
> implemented. It should be more or less easy to add the same option for
> C++ (even C_INCLUDE_DIRS seems to be tinkered in to me).
> I just wanted to file a bug about this because fixing this is not
> trivial and I am not sure whether I will find the time right away to fix it.
> Fixing it would also have the benefit that I could send the patch to the
> LLVM mailing list and we might see the change upstream in the next LLVM
> version.
>
> Tim.

Just put everything into `C_INCLUDE_DIRS' should make it work, see:

https://github.com/trivialfis/guixpkgs/blob/c8a6871d2757557581640d7a14b4c9167459cb14/llvm.scm#L100

Using clang/clang++ from above link to compile a single translation unit should
work.  And there is `cquery' in `code.scm' within that repository, which relies
on clang to work, you can try it out.

It shouldn't take long to make LLVM and Clang in there ready to be merge in
core-update or staging (I don't know yet), it's just I don't feel comfortable
with the `clang-from-llvm' in guix, maybe someone could help carrying it out.

Jiaming

bug#32773: clang: missing default include paths for C++

[Robin Templeton]

Hi Tim,

Tim Gesthuizen <tim.gesthuizen@yahoo.de> writes:

> As you can see from the output, clang is missing some include paths that
> gcc has. Specifying a custom `CPLUS_INCLUDE_PATH' fixes the problem:
>
> ┌────
> │
> CPLUS_INCLUDE_PATH=$HOME/.guix-profile/include/c++:$HOME/.guix-profile/include/c++/x86_64-unknown-linux-gnu/
> clang++ test.cc
> │ ./a.out
> └────
>
> ┌────
> │ Hello, World
> └────
>
> This is already done in the package definition for the
> `C_INCLUDE_PATH'. It is not done for C++ because clang does not
> implement a feature or build system variable for changing it.
>
> Fixing this problem would probably include an upstream patch enabling a
> similar feature for C++ for what is already done in C and configuring
> this variable in build phase to add the same include paths that g++ has.

Another solution, maybe simpler than a new environment variable, is to
have clang use the C++ include path from its gcc input. On FHS systems,
clang can find C++ headers using the GCC_INSTALL_PREFIX configure
option, but it doesn't work under Guix because the GCC package puts
headers and libraries in separate outputs. Guix already patches clang to
hardcode some library directories; maybe something similar could be done
for C++ headers. (I think the function to modify for this would be
Linux::addLibStdCxxIncludePaths in lib/Driver/ToolChains/Linux.cpp.)

bug#32773: clang: missing default include paths for C++

[Tim Gesthuizen]

On 22.09.2018 02:58, Robin Templeton wrote:
> Hi Tim,
> 
> Tim Gesthuizen <tim.gesthuizen@yahoo.de> writes:
> 
>> As you can see from the output, clang is missing some include paths that
>> gcc has. Specifying a custom `CPLUS_INCLUDE_PATH' fixes the problem:
>>
>> ┌────
>> │
>> CPLUS_INCLUDE_PATH=$HOME/.guix-profile/include/c++:$HOME/.guix-profile/include/c++/x86_64-unknown-linux-gnu/
>> clang++ test.cc
>> │ ./a.out
>> └────
>>
>> ┌────
>> │ Hello, World
>> └────
>>
>> This is already done in the package definition for the
>> `C_INCLUDE_PATH'. It is not done for C++ because clang does not
>> implement a feature or build system variable for changing it.
>>
>> Fixing this problem would probably include an upstream patch enabling a
>> similar feature for C++ for what is already done in C and configuring
>> this variable in build phase to add the same include paths that g++ has.
> 
> Another solution, maybe simpler than a new environment variable, is to
> have clang use the C++ include path from its gcc input. On FHS systems,
> clang can find C++ headers using the GCC_INSTALL_PREFIX configure
> option, but it doesn't work under Guix because the GCC package puts
> headers and libraries in separate outputs. Guix already patches clang to
> hardcode some library directories; maybe something similar could be done
> for C++ headers. (I think the function to modify for this would be
> Linux::addLibStdCxxIncludePaths in lib/Driver/ToolChains/Linux.cpp.)
> 

Hi Robin,
I also found that section and the environment variable while debugging
clang. I did not know about that variable even though its documented and
Guix uses it. I've created a debug build of clang for investigating and
pointing GCC_INSTALL_PREFIX to the GCC input and not the lib part fixes
the problem for me. I don't know from where this build pulls crt1.o. I
will try changing GCC_INSTALL_PREFIX in the guix package definition and
see whether that fixes the bug.

Tim.

bug#32773: [PATCH] Fix clang libstdc++ header location search

[David Truby]

---
 gnu/packages/llvm.scm | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/gnu/packages/llvm.scm b/gnu/packages/llvm.scm
index 33fb53d65e..0a7efe980f 100644
--- a/gnu/packages/llvm.scm
+++ b/gnu/packages/llvm.scm
@@ -202,6 +202,7 @@ compiler.  In LLVM this library is called \"compiler-rt\".")
                    (lambda* (#:key inputs #:allow-other-keys)
                      (let ((libc (assoc-ref inputs "libc"))
                            (compiler-rt (assoc-ref inputs "clang-runtime"))
+                           (gcc (assoc-ref inputs "gcc"))
                            (version
                             (string->number
                              ,(version-major (package-version clang-runtime)))))
@@ -218,6 +219,10 @@ compiler.  In LLVM this library is called \"compiler-rt\".")
                             (("(^[[:blank:]]+LibDir = ).*" _ declaration)
                              (string-append declaration "\"" libc "/lib\";\n"))
 
+                            ;; Make clang look for libstdc++ in the right location
+                            (("LibStdCXXIncludePathCandidates\\[\\] = \\{")
+                             (string-append "LibStdCXXIncludePathCandidates[] = { \"" gcc "/include/c++\","))
+
                             ;; Make sure libc's libdir is on the search path, to
                             ;; allow crt1.o & co. to be found.
                             (("@GLIBC_LIBDIR@")
-- 
2.24.0

bug#32773: [PATCH] Fix clang libstdc++ header location search

[Carl Dong]

Hi David!

This patch is most welcome, I’m wondering if you think it’d be possible to add more details in the comments for future readers of the code. See below.

> On Nov 13, 2019, at 11:56 AM, David Truby <David.Truby@arm.com> wrote:
> 
> +                            ;; Make clang look for libstdc++ in the right location
> +                            (("LibStdCXXIncludePathCandidates\\[\\] = \\{")
> +                             (string-append "LibStdCXXIncludePathCandidates[] = { \"" gcc "/include/c++\","))
I believe the reason why clang’s “auto detection” fails here is because it expects the /include dir containing c++ to be under the same directory as LibDir, correct? Perhaps we can note that since in Guix, we put the libs in a separate output, we invalidate the aforementioned expectation, and this is why we need to manually add this path.

Another point: Perhaps we can add the path on a separate line instead of it being on the same line?

Otherwise, looks great!

Cheers,
Carl Dong

bug#32773: [PATCH] Fix clang libstdc++ header location search

[Mathieu Othacehe]

Hello David,

This patch is a real progress, thank you! However, I still have a
linking error when compiling a trivial test program with clang:

mathieu@elbruz ~/guix [env]$ ./pre-inst-env guix environment --ad-hoc clang --pure
mathieu@elbruz ~/guix [env]$ clang ~/tmp/t.cpp 
clang-8: error: unable to execute command: Executable "ld" doesn't exist!
clang-8: error: linker command failed with exit code 1 (use -v to see invocation)

This is because the linker provided by "binutils" is not accessible. I
guess we need to make something analog to make-gcc-toolchain.

WDYT?

Mathieu

David Truby writes:

> ---
>  gnu/packages/llvm.scm | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/gnu/packages/llvm.scm b/gnu/packages/llvm.scm
> index 33fb53d65e..0a7efe980f 100644
> --- a/gnu/packages/llvm.scm
> +++ b/gnu/packages/llvm.scm
> @@ -202,6 +202,7 @@ compiler.  In LLVM this library is called \"compiler-rt\".")
>                     (lambda* (#:key inputs #:allow-other-keys)
>                       (let ((libc (assoc-ref inputs "libc"))
>                             (compiler-rt (assoc-ref inputs "clang-runtime"))
> +                           (gcc (assoc-ref inputs "gcc"))
>                             (version
>                              (string->number
>                               ,(version-major (package-version clang-runtime)))))
> @@ -218,6 +219,10 @@ compiler.  In LLVM this library is called \"compiler-rt\".")
>                              (("(^[[:blank:]]+LibDir = ).*" _ declaration)
>                               (string-append declaration "\"" libc "/lib\";\n"))
>  
> +                            ;; Make clang look for libstdc++ in the right location
> +                            (("LibStdCXXIncludePathCandidates\\[\\] = \\{")
> +                             (string-append "LibStdCXXIncludePathCandidates[] = { \"" gcc "/include/c++\","))
> +
>                              ;; Make sure libc's libdir is on the search path, to
>                              ;; allow crt1.o & co. to be found.
>                              (("@GLIBC_LIBDIR@")

bug#32773: [PATCH] Fix clang libstdc++ header location search

[David Truby]

Hi Mathieu,

> mathieu@elbruz ~/guix [env]$ ./pre-inst-env guix environment --ad-hoc 
> clang --pure
> mathieu@elbruz ~/guix [env]$ clang ~/tmp/t.cpp 
> clang-8: error: unable to execute command: Executable "ld" doesn't
> exist!
> clang-8: error: linker command failed with exit code 1 (use -v to see
> invocation)

Interesting, for some reason this worked for me. Although now that I
think about it I may not have used a pure environment, because I do
remember seeing this before. 

> 
> This is because the linker provided by "binutils" is not accessible.
> I
> guess we need to make something analog to make-gcc-toolchain.

I think adding gcc-toolchain to propagated-inputs should work in
principle, other than the fact that the gcc used for gcc-lib and
libstdc++ need to be the same as the propagated gcc-toolchain. I did
have a fix for this but I'm not sure if it's the best way of writing
it.
I'll send another patch with the fix though so at least others can
comment on it!

David Truby

bug#32773: [PATCH] Fix clang libstdc++ header location search

[Mathieu Othacehe]

[-- Attachment #1: Type: text/plain, Size: 544 bytes --]


> I think adding gcc-toolchain to propagated-inputs should work in
> principle, other than the fact that the gcc used for gcc-lib and
> libstdc++ need to be the same as the propagated gcc-toolchain. I did
> have a fix for this but I'm not sure if it's the best way of writing
> it.
> I'll send another patch with the fix though so at least others can
> comment on it!

Yes propagating gcc-toolchain would work but, would also cause gcc to be
available as a side effect. Maybe the patch attached, on top of yours,
would work?

Thanks,

Mathieu

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: 0001-gnu-Add-clang-toolchain.patch --]
[-- Type: text/x-diff, Size: 3501 bytes --]

From ea662ff1ed62183ae0036242f53a14bb0889cb47 Mon Sep 17 00:00:00 2001
From: Mathieu Othacehe <m.othacehe@gmail.com>
Date: Thu, 14 Nov 2019 13:25:00 +0100
Subject: [PATCH] gnu: Add clang-toolchain.

* gnu/packages/llvm.scm (make-clang-toolchain): New method.
(clang-toolchain): New public variable defined using previous method.
---
 gnu/packages/llvm.scm | 50 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/gnu/packages/llvm.scm b/gnu/packages/llvm.scm
index 0a7efe980f..8c47b884ae 100644
--- a/gnu/packages/llvm.scm
+++ b/gnu/packages/llvm.scm
@@ -37,7 +37,9 @@
   #:use-module (guix build-system cmake)
   #:use-module (guix build-system emacs)
   #:use-module (guix build-system python)
+  #:use-module (guix build-system trivial)
   #:use-module (gnu packages)
+  #:use-module (gnu packages base)
   #:use-module (gnu packages gcc)
   #:use-module (gnu packages bootstrap)           ;glibc-dynamic-linker
   #:use-module (gnu packages compression)
@@ -295,6 +297,51 @@ project includes the Clang front end, the Clang static analyzer, and several
 code analysis tools.")
     (license license:ncsa)))
 
+(define (make-clang-toolchain clang)
+  (package
+    (name (string-append (package-name clang) "-toolchain"))
+    (version (package-version clang))
+    (source #f)
+    (build-system trivial-build-system)
+    (arguments
+     '(#:modules ((guix build union))
+       #:builder (begin
+                   (use-modules (ice-9 match)
+                                (srfi srfi-26)
+                                (guix build union))
+
+                   (let ((out (assoc-ref %outputs "out")))
+
+                     (match %build-inputs
+                       (((names . directories) ...)
+                        (union-build out directories)))
+
+                     (union-build (assoc-ref %outputs "debug")
+                                  (list (assoc-ref %build-inputs
+                                                   "libc-debug")))
+                     (union-build (assoc-ref %outputs "static")
+                                  (list (assoc-ref %build-inputs
+                                                   "libc-static")))
+                     #t))))
+
+    (native-search-paths (package-native-search-paths clang))
+    (search-paths (package-search-paths clang))
+
+    (license (package-license clang))
+    (home-page "https://clang.llvm.org")
+    (synopsis "Complete Clang toolchain for C/C++ development")
+    (description "This package provides a complete Clang toolchain for C/C++
+development to be installed in user profiles.  This includes Clang, as well as
+libc (headers and binaries, plus debugging symbols in the @code{debug}
+output), and Binutils.")
+    (outputs '("out" "debug" "static"))
+    (inputs `(("clang" ,clang)
+              ("ld-wrapper" ,(car (assoc-ref (%final-inputs) "ld-wrapper")))
+              ("binutils" ,binutils)
+              ("libc" ,glibc)
+              ("libc-debug" ,glibc "debug")
+              ("libc-static" ,glibc "static")))))
+
 (define-public libcxx
   (package
     (name "libcxx")
@@ -404,6 +451,9 @@ with that of libgomp, the GNU Offloading and Multi Processing Library.")
                    "0svk1f70hvpwrjp6x5i9kqwrqwxnmcrw5s7f4cxyd100mdd12k08"
                    #:patches '("clang-7.0-libc-search-path.patch")))
 
+(define-public clang-toolchain
+  (make-clang-toolchain clang))
+
 (define-public llvm-7
   (package
     (inherit llvm)
-- 
2.24.0

bug#32773: [PATCH] Fix clang libstdc++ header location search

[David Truby]

Hi Mathieu,

Applying both your patch and my patch works for me, in both pure and
non-pure environments. I would suggest taht we also hide clang in the
same way as gcc is hidden (in favour of clang-toolchain) to avoid
confusion, but otherwise it seems these two patches together at least
get things to a working state!

I'd like to see make-clang-toolchain allow you to pick between a
specific libstdc++ or libc++, but that requires more thinking so I
think ideally it'd be better to apply these patches first to get things
to a fixed state.

Thanks
David Truby

On Thu, 2019-11-14 at 14:40 +0100, Mathieu Othacehe wrote:
> > I think adding gcc-toolchain to propagated-inputs should work in
> > principle, other than the fact that the gcc used for gcc-lib and
> > libstdc++ need to be the same as the propagated gcc-toolchain. I
> > did
> > have a fix for this but I'm not sure if it's the best way of
> > writing
> > it.
> > I'll send another patch with the fix though so at least others can
> > comment on it!
> 
> Yes propagating gcc-toolchain would work but, would also cause gcc to
> be
> available as a side effect. Maybe the patch attached, on top of
> yours,
> would work?
> 
> Thanks,
> 
> Mathieu

bug#32773: [PATCH] Fix clang libstdc++ header location search

[Mathieu Othacehe]

> Applying both your patch and my patch works for me, in both pure and
> non-pure environments. I would suggest taht we also hide clang in the
> same way as gcc is hidden (in favour of clang-toolchain) to avoid
> confusion, but otherwise it seems these two patches together at least
> get things to a working state!

Great! 

> I'd like to see make-clang-toolchain allow you to pick between a
> specific libstdc++ or libc++, but that requires more thinking so I
> think ideally it'd be better to apply these patches first to get things
> to a fixed state.

I agree. Let's wait to see if someone has objections and I'll push both
patches in a few days.

Thanks for your support on this :)

Mathieu

bug#32773: [PATCH] Fix clang libstdc++ header location search

[David Truby]

No problem, happy to help!

I'm also vaguely thinking if there's a way to upstream some of this
stuff in to clang so that we aren't patching it manually here. The same
file that we're patching has stuff specifically for other distros (e.g.
it has some Gentoo and Cray Linux specific fixes) so I don't think
they'd be opposed to accepting patches that are specific to Guix.
I'm not sure what the answer is there though, as we still need to patch
in the full path to the headers... maybe a cmake option and associated
macro to be used in that file? 

Not that this has any bearing on accepting these patches now, it's just
another thought for the future :)

David Truby

On Thu, 2019-11-14 at 17:54 +0100, Mathieu Othacehe wrote:
> > Applying both your patch and my patch works for me, in both pure
> > and
> > non-pure environments. I would suggest taht we also hide clang in
> > the
> > same way as gcc is hidden (in favour of clang-toolchain) to avoid
> > confusion, but otherwise it seems these two patches together at
> > least
> > get things to a working state!
> 
> Great! 
> 
> > I'd like to see make-clang-toolchain allow you to pick between a
> > specific libstdc++ or libc++, but that requires more thinking so I
> > think ideally it'd be better to apply these patches first to get
> > things
> > to a fixed state.
> 
> I agree. Let's wait to see if someone has objections and I'll push
> both
> patches in a few days.
> 
> Thanks for your support on this :)
> 
> Mathieu

bug#32773: [PATCH] Fix clang libstdc++ header location search

[Mathieu Othacehe]

> I'm not sure what the answer is there though, as we still need to patch
> in the full path to the headers... maybe a cmake option and associated
> macro to be used in that file? 

They already have a CMake option to select libc++ or libstdc++, so
adding another option to specify the path of the selected C++ library
would be really nice.

Plus it would benefit Nix and other distros where the path of those
libraries cannot be guessed.

Mathieu

bug#32773: [PATCH] Fix clang libstdc++ header location search

[Mathieu Othacehe]

Hello,

I edited your patch to include a copyright line, adapted commit log
message to our conventions and pushed it! Please tell me if you want a
different copyright.

I also pushed my patch adding clang-toolchain packages.

Thanks,

Mathieu

bug#32773: [PATCH] Fix clang libstdc++ header location search

[David Truby]

Hi Mathier,

Thanks for merging this! Would it be possible to change the copyright
to Arm Ltd. but leave my email as the point of contact? Please let me
know if this is an issue.

Thanks
David Truby

On Sun, 2019-11-17 at 12:21 +0100, Mathieu Othacehe wrote:
> Hello,
> 
> I edited your patch to include a copyright line, adapted commit log
> message to our conventions and pushed it! Please tell me if you want
> a
> different copyright.
> 
> I also pushed my patch adding clang-toolchain packages.
> 
> Thanks,
> 
> Mathieu

bug#32773: [PATCH] Fix clang libstdc++ header location search

[Mathieu Othacehe]

> Thanks for merging this! Would it be possible to change the copyright
> to Arm Ltd. but leave my email as the point of contact? Please let me
> know if this is an issue.

No I guess its ok. Pushed!

Mathieu

bug#32773: [PATCH] Fix clang libstdc++ header location search

[Ludovic Courtès]

Mathieu Othacehe <m.othacehe@gmail.com> skribis:

> From ea662ff1ed62183ae0036242f53a14bb0889cb47 Mon Sep 17 00:00:00 2001
> From: Mathieu Othacehe <m.othacehe@gmail.com>
> Date: Thu, 14 Nov 2019 13:25:00 +0100
> Subject: [PATCH] gnu: Add clang-toolchain.
>
> * gnu/packages/llvm.scm (make-clang-toolchain): New method.
> (clang-toolchain): New public variable defined using previous method.

Nice, LGTM!

Thanks,
Ludo’.

bug#32773: [PATCH] Fix clang libstdc++ header location search

[Ludovic Courtès]

Hello,

Mathieu Othacehe <m.othacehe@gmail.com> skribis:

> mathieu@elbruz ~/guix [env]$ ./pre-inst-env guix environment --ad-hoc clang --pure

Isn’t it enough to add ‘ld-wrapper’ to the environment?

Thanks,
Ludo’.