bug#57380: 29.0.50; configure --config-cache --with-native-compilation failing

[Gerd Möllmann]

Gerd Möllmann <gerd.moellmann@gmail.com> writes:

>
> Gerd Möllmann <gerd.moellmann@gmail.com> writes:
>
>> AC_RUN_IFELSE is apparently run differently when using the cache, or
>> something like that.
>
> Success and failure
>
> configure:19674: gcc -o conftest -g3 -O2 ...   conftest.c
> configure:19674: gcc -o conftest -g -O2  ...   conftest.m
>                                                        ^^
>
> Baffled.

diff --git a/configure.ac b/configure.ac
index 7616e450d0..08a41a7808 100644
--- a/configure.ac
+++ b/configure.ac
@@ -4273,6 +4273,7 @@ AC_DEFUN
       [], [libgccjit_not_found])
     AC_CHECK_HEADERS([libgccjit.h], [], [libgccjit_dev_not_found])
     # Check if libgccjit really works.
+    AC_LANG(C)
     AC_RUN_IFELSE([libgccjit_smoke_test], [], [libgccjit_broken])
     HAVE_NATIVE_COMP=yes
     case "${opsys}" in

This makes it work for me.

It that something for emacs-28, or rather not? Guess not, but just in
case.