Use flexmembers on IBM XL C for AIX

This removes a workaround where Emacs did not use flexible
array members when compiled with IBM XL C.  Instead, avoid
the problem by making the aliasing issues more obvious to
this compiler.
* admin/merge-gnulib: Don’t remove m4/flexmember.m4.
* m4/flexmember.m4: Copy from gnulib.
* configure.ac (AC_C_FLEXIBLE_ARRAY_MEMBER): Remove workaround.
* src/alloc.c (allocate_string_data): Rephrase to avoid aliasing
problem that would otherwise mess up code generated for flexible
array members by IBM XL C for AIX, V12.1.
* src/conf_post.h (FLEXIBLE_ARRAY_MEMBER): Remove; now done
by gnulib code.

1 files changed, 1 insertions, 1 deletions

diff --git a/admin/merge-gnulib b/admin/merge-gnulib
index 1e3b7599626..ada80b4ae86 100755
--- a/admin/merge-gnulib
+++ b/admin/merge-gnulib
@@ -93,7 +93,7 @@ test -x "$gnulib_srcdir"/gnulib-tool || {
 }
 
 "$gnulib_srcdir"/gnulib-tool --dir="$src" $GNULIB_TOOL_FLAGS $GNULIB_MODULES &&
-rm -- "$src"lib/gl_openssl.h "$src"m4/fcntl-o.m4 "$src"m4/flexmember.m4 \
+rm -- "$src"lib/gl_openssl.h "$src"m4/fcntl-o.m4 \
       "$src"m4/gl-openssl.m4 \
       "$src"m4/gnulib-cache.m4"$src" m4/warn-on-use.m4 &&
 cp -- "$gnulib_srcdir"/build-aux/texinfo.tex "$src"doc/misc &&