Limit <config.h>’s includes

This follows up on recent problems with the fact that config.h
includes stdlib.h etc.; some files need to include stdlib.h later.
config.h generally should limit itself to includes that are
universally safe; outside of MS-Windows, only stdbool.h makes
the cut among the files currently included.  So, move the
other includes to just the files that need them (Bug#24506).
* configure.ac (config_opsysfile): Remove, as this generic hook
is no longer needed.
* lib-src/etags.c, src/unexmacosx.c, src/w32.c, src/w32notify.c:
* src/w32proc.c (_GNU_SOURCE):
Remove, as it’s OK for config.h to do this now.
* src/conf_post.h: Include <ms-w32.h>, instead of the generic
config_opsysfile, for simplicity as this old way of configuring is
now done only for the MS-Windows port.  Do not include <ms-w32.h>
if DEFER_MS_W32_H, for the benefit of the few files that want its
effects later.  Do not include <alloca.h>, <string.h>, or
<stdlib.h>.  Other files modified to include these headers as
needed, or to not include headers that are no longer needed.
* src/lisp.h: Include <alloca.h> and <string.h> here, since
some of the inline functions need them.
* src/regex.c: Include <alloca.h> if not emacs.  (If emacs,
we can rely on SAFE_ALLOCA.)  There is no longer any need to
worry about HAVE_ALLOCA_H.
* src/unexmacosx.c: Rely on config.h not including stdlib.h.
* src/w32.c, src/w32notify.c, src/w32proc.c (DEFER_MS_W32_H):
Define before including <config.h> first, and include <ms-w32.h>
after the troublesome headers.

1 files changed, 5 insertions, 9 deletions

diff --git a/src/unexmacosx.c b/src/unexmacosx.c
index 185a9d1f62b..ea8e884f177 100644
--- a/src/unexmacosx.c
+++ b/src/unexmacosx.c
@@ -85,20 +85,16 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
    be changed accordingly.
 */
 
-/* Enable GNU extensions in gnulib replacement headers.  */
-#define _GNU_SOURCE 1
-
-/* config.h #define:s malloc/realloc/free and then includes stdlib.h.
-   We want the undefined versions, but if config.h includes stdlib.h
-   with the #define:s in place, the prototypes will be wrong and we get
-   warnings.  To prevent that, include stdlib.h before config.h.  */
-
-#include <stdlib.h>
 #include <config.h>
+
+/* Although <config.h> redefines malloc to unexec_malloc, etc., this
+   file wants stdlib.h to declare the originals.  */
 #undef malloc
 #undef realloc
 #undef free
 
+#include <stdlib.h>
+
 #include "unexec.h"
 #include "lisp.h"