bug#47783: 28.0.50; [feature/native-comp] libgccjit.so: error: error invoking gcc driver

[Pankaj Jangid <pankaj@codeisgreat.org>]

Andrea Corallo via "Bug reports for GNU Emacs, the Swiss army knife of
text editors" <bug-gnu-emacs@gnu.org> writes:

> I don't know what happened here but I bet has to do with the value of
> one of these three env vars [1] and most likely PATH.
>
> [1] <https://gcc.gnu.org/onlinedocs/jit/internals/index.html#environment-variables>
>

I am working with pre-built version of ‘gcc’ and ‘libgccjit’ from
Homebrew. So I tried to set the following environment
variables. Experimented with various permutation combinations of these.

#+begin_src elisp
(add-to-list 'exec-path
             "/usr/local/opt/gcc/bin")
(setenv "PATH" (mapconcat 'identity exec-path ":"))        
(setenv "LD_LIBRARY_PATH"
        "/usr/local/opt/libgccjit/lib/gcc/10:/usr/local/opt/gcc/lib/gcc/10")
(setenv "LIBRARY_PATH"
        "/usr/local/opt/libgccjit/lib/gcc/10:/usr/local/opt/gcc/lib/gcc/10")
#end_src

The above are standard location of ‘gcc’ and ’libgccjit’ artifacts.

The exec-path configuration above crashes my Emacs at startup. So I had
to comment that out.
\f

Is there a way in Emacs to get all the environment variables in one go?
I want to compare the vars from two invocations - GUI and CLI. As I
reported earlier that CLI invocation works without any error.
\f

More facts:

The error comes only at the beginning. As you can see in the following
log (*Async-native-compilation-log) that compilation is working fine
later on.

--8<---------------cut here---------------start------------->8---
Compiling /Users/pankaj/Applications/Emacs.app/Contents/Resources/lisp/emacs-lisp/cl-lib.el.gz...
uncompressing cl-lib.el.gz...
uncompressing cl-lib.el.gz...done
ld: library not found for -lgcc_ext.10.5
libgccjit.so: error: error invoking gcc driver
/Users/pankaj/Applications/Emacs.app/Contents/Resources/lisp/emacs-lisp/cl-lib.el.gz: Error: Internal native compiler error failed to compile
Compiling /Users/pankaj/Applications/Emacs.app/Contents/Resources/lisp/emacs-lisp/crm.el.gz...
uncompressing crm.el.gz...
uncompressing crm.el.gz...done
Compiling /Users/pankaj/Applications/Emacs.app/Contents/Resources/lisp/progmodes/hideshow.el.gz...
uncompressing hideshow.el.gz...
uncompressing hideshow.el.gz...done
Compiling /Users/pankaj/Applications/Emacs.app/Contents/Resources/lisp/emacs-lisp/advice.el.gz...
uncompressing advice.el.gz...
uncompressing advice.el.gz...done
Compiling /Users/pankaj/Applications/Emacs.app/Contents/Resources/lisp/outline.el.gz...
uncompressing outline.el.gz...
uncompressing outline.el.gz...done
Compiling /Users/pankaj/Applications/Emacs.app/Contents/Resources/lisp/calendar/cal-menu.el.gz...
uncompressing cal-menu.el.gz...
uncompressing cal-menu.el.gz...done
--8<---------------cut here---------------end--------------->8---

And when all the compilation is done the error goes away; it does not
appear in further sessions.