Re: Messed up gl_COMPILER_PREPARE_CHECK_DECL

[Paul Eggert]

On 1/10/20 2:47 PM, Bruno Haible wrote:
> Thanks for the simple-to-reproduce recipe. I've pushed this fix:

Unfortunately even with that fix I still have trouble building Emacs. 
That is, with this recipe:

mkdir d
cd d
git clone https://git.savannah.gnu.org/git/emacs.git
cd emacs
admin/merge-gnulib
./autogen.sh
./configure
make

(same recipe as before, but now with "configure; make" at the end) the 
build now fails this way:

  CC       strtoimax.o
strtoimax.c:44:15: error: redundant redeclaration of ‘strtoll’ 
[-Werror=redundant-decls]
   44 | long long int strtoll (char const *, char **, int);
      |               ^~~~~~~
In file included from ./stdlib.h:36,
                 from strtoimax.c:26:
/usr/include/stdlib.h:200:22: note: previous declaration of ‘strtoll’ 
was here
  200 | extern long long int strtoll (const char *__restrict __nptr,
      |                      ^~~~~~~
make[1]: *** [Makefile:95: strtoimax.o] Error 1
make[1]: *** Waiting for unfinished jobs....
make[1]: Leaving directory '/home/eggert/src/gnu/emacs/static-checking/lib'
make: *** [Makefile:411: lib] Error 2


The above diagnostic comes because src/config.h contains the line 
"#define HAVE_DECL_STRTOLL 0" which is incorrect for this platform. And 
that incorrect line comes because ac_compile_for_check_decl is used 
before it is set. And this occurs because Emacs's configure.ac's first 
use of AC_CHECK_DECL is executed only on alpha platforms (which my 
platform is not), which means the initialization of 
ac_compile_for_check_decl is skipped.