Hi Guix,

Guile Emacs can no longer be built.  GCC fails a configure test:

~~~~~~~~~~~~~
checking for gcc... gcc
checking whether the C compiler works... no
configure: error: in `/tmp/guix-build-guile-emacs-20150512.41120e0.drv-0/source':
configure: error: C compiler cannot create executables
See `config.log' for more details
~~~~~~~~~~~~~

“config.log” reveals that GCC failed on the following trivial file:

~~~~~~~~~~~~~
/* confdefs.h */
#define PACKAGE_NAME "GNU Emacs"
#define PACKAGE_TARNAME "emacs"
#define PACKAGE_VERSION "24.4.50"
#define PACKAGE_STRING "GNU Emacs 24.4.50"
#define PACKAGE_BUGREPORT "bug-gnu-emacs@gnu.org"
#define PACKAGE_URL "http://www.gnu.org/software/emacs/"
#define PACKAGE "emacs"
#define VERSION "24.4.50"
#define MAIL_USE_POP 1
/* end confdefs.h.  */

int
main ()
{

  ;
  return 0;
}
~~~~~~~~~~~~~

So I opened an environment with “guix environment --pure guile-emacs”
and ran “gcc --verbose conftest.c”, where “conftest.c” contains the test
programme above.  This is what I get:

~~~~~~~~~~~~~
rekado@banana in source [env]: gcc --verbose conftest.c 
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/gnu/store/pg8nnqprjxgwhwiyh8nhbphzj53ax77i-gcc-4.9.3/libexec/gcc/x86_64-unknown-linux-gnu/4.9.3/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: 
Thread model: posix
gcc version 4.9.3 (GCC) 
COLLECT_GCC_OPTIONS='-v' '-mtune=generic' '-march=x86-64'
 /gnu/store/pg8nnqprjxgwhwiyh8nhbphzj53ax77i-gcc-4.9.3/libexec/gcc/x86_64-unknown-linux-gnu/4.9.3/cc1 -quiet -v conftest.c -quiet -dumpbase conftest.c -mtune=generic -march=x86-64 -auxbase conftest -version -o /tmp/ccp7oiXi.s
GNU C (GCC) version 4.9.3 (x86_64-unknown-linux-gnu)
	compiled by GNU C version 4.9.3, GMP version 6.0.0, MPFR version 3.1.3, MPC version 1.0.3
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/pkasxagsa4z4viscfpl6sjszmdmwncl1-gcc-4.9.3-lib/lib/gcc/x86_64-unknown-linux-gnu/4.9.3/../../../../../../../x86_64-unknown-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
 /gnu/store/b2r0dq25720qilqr4m4a436gxy8ppml3-profile/include
 /gnu/store/pkasxagsa4z4viscfpl6sjszmdmwncl1-gcc-4.9.3-lib/lib/gcc/x86_64-unknown-linux-gnu/4.9.3/include
 /gnu/store/pkasxagsa4z4viscfpl6sjszmdmwncl1-gcc-4.9.3-lib/lib/gcc/x86_64-unknown-linux-gnu/4.9.3/include-fixed
 /gnu/store/sgzfawy95pfn7nsw3xvmca58llm5zzbc-glibc-2.22/include
End of search list.
GNU C (GCC) version 4.9.3 (x86_64-unknown-linux-gnu)
	compiled by GNU C version 4.9.3, GMP version 6.0.0, MPFR version 3.1.3, MPC version 1.0.3
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: b87adce59d40c64e9bafeee32b3f9c51
COLLECT_GCC_OPTIONS='-v' '-mtune=generic' '-march=x86-64'
 as -v --64 -o /tmp/ccNJYsWO.o /tmp/ccp7oiXi.s
GNU assembler version 2.25.1 (x86_64-unknown-linux-gnu) using BFD version (GNU Binutils) 2.25.1
COMPILER_PATH=/gnu/store/pg8nnqprjxgwhwiyh8nhbphzj53ax77i-gcc-4.9.3/libexec/gcc/x86_64-unknown-linux-gnu/4.9.3/:/gnu/store/pg8nnqprjxgwhwiyh8nhbphzj53ax77i-gcc-4.9.3/libexec/gcc/x86_64-unknown-linux-gnu/4.9.3/:/gnu/store/pg8nnqprjxgwhwiyh8nhbphzj53ax77i-gcc-4.9.3/libexec/gcc/x86_64-unknown-linux-gnu/:/gnu/store/pkasxagsa4z4viscfpl6sjszmdmwncl1-gcc-4.9.3-lib/lib/gcc/x86_64-unknown-linux-gnu/4.9.3/:/gnu/store/pkasxagsa4z4viscfpl6sjszmdmwncl1-gcc-4.9.3-lib/lib/gcc/x86_64-unknown-linux-gnu/
LIBRARY_PATH=/gnu/store/b2r0dq25720qilqr4m4a436gxy8ppml3-profile/lib/:/gnu/store/pkasxagsa4z4viscfpl6sjszmdmwncl1-gcc-4.9.3-lib/lib/gcc/x86_64-unknown-linux-gnu/4.9.3/:/gnu/store/pkasxagsa4z4viscfpl6sjszmdmwncl1-gcc-4.9.3-lib/lib/gcc/x86_64-unknown-linux-gnu/4.9.3/../../../:/gnu/store/sgzfawy95pfn7nsw3xvmca58llm5zzbc-glibc-2.22/lib
COLLECT_GCC_OPTIONS='-v' '-mtune=generic' '-march=x86-64'
 /gnu/store/pg8nnqprjxgwhwiyh8nhbphzj53ax77i-gcc-4.9.3/libexec/gcc/x86_64-unknown-linux-gnu/4.9.3/collect2 -plugin /gnu/store/pg8nnqprjxgwhwiyh8nhbphzj53ax77i-gcc-4.9.3/libexec/gcc/x86_64-unknown-linux-gnu/4.9.3/liblto_plugin.so -plugin-opt=/gnu/store/pg8nnqprjxgwhwiyh8nhbphzj53ax77i-gcc-4.9.3/libexec/gcc/x86_64-unknown-linux-gnu/4.9.3/lto-wrapper -plugin-opt=-fresolution=/tmp/ccpvCgWk.res -plugin-opt=-pass-through=-lgcc -plugin-opt=-pass-through=-lgcc_s -plugin-opt=-pass-through=-lgcc_s -plugin-opt=-pass-through=-lc -plugin-opt=-pass-through=-lgcc -plugin-opt=-pass-through=-lgcc_s --eh-frame-hdr -m elf_x86_64 -dynamic-linker /gnu/store/sgzfawy95pfn7nsw3xvmca58llm5zzbc-glibc-2.22/lib/ld-linux-x86-64.so.2 /gnu/store/b2r0dq25720qilqr4m4a436gxy8ppml3-profile/lib/crt1.o /gnu/store/b2r0dq25720qilqr4m4a436gxy8ppml3-profile/lib/crti.o /gnu/store/pkasxagsa4z4viscfpl6sjszmdmwncl1-gcc-4.9.3-lib/lib/gcc/x86_64-unknown-linux-gnu/4.9.3/crtbegin.o -L/gnu/store/b2r0dq25720qilqr4m4a436gxy8ppml3-profile/lib -L/gnu/store/pkasxagsa4z4viscfpl6sjszmdmwncl1-gcc-4.9.3-lib/lib/gcc/x86_64-unknown-linux-gnu/4.9.3 -L/gnu/store/pkasxagsa4z4viscfpl6sjszmdmwncl1-gcc-4.9.3-lib/lib/gcc/x86_64-unknown-linux-gnu/4.9.3/../../.. -L/gnu/store/sgzfawy95pfn7nsw3xvmca58llm5zzbc-glibc-2.22/lib /tmp/ccNJYsWO.o -lgcc --as-needed -lgcc_s --no-as-needed -L/gnu/store/sgzfawy95pfn7nsw3xvmca58llm5zzbc-glibc-2.22/lib -rpath=/gnu/store/sgzfawy95pfn7nsw3xvmca58llm5zzbc-glibc-2.22/lib -rpath=/gnu/store/pkasxagsa4z4viscfpl6sjszmdmwncl1-gcc-4.9.3-lib/lib -lgcc_s -lc -lgcc --as-needed -lgcc_s --no-as-needed /gnu/store/pkasxagsa4z4viscfpl6sjszmdmwncl1-gcc-4.9.3-lib/lib/gcc/x86_64-unknown-linux-gnu/4.9.3/crtend.o /gnu/store/b2r0dq25720qilqr4m4a436gxy8ppml3-profile/lib/crtn.o
collect2: error: ld terminated with signal 6 [Aborted]
Throw without catch before boot:
Aborting.
~~~~~~~~~~~~~

“Throw without catch before boot” actually sounds like a Guile error, so
I looked at whether there have been any changes to
“guile-for-guile-emacs” (or “guile-next” from which it inherits)
recently, and yes: commit dd90ed892a7dbe13a214b2d7ebf321b866211374
changed the search paths for “guile-next”, which broke
“guile-for-guile-emacs”.

The attached patch adds a “native-search-paths” field to
“guile-for-guile-emacs” to override the one specified by “guile-next”.

~~ Ricardo