bug#24506: [PROPOSED PATCH] Limit <config.h>’s includes

bug#24506: [PROPOSED PATCH] Limit <config.h>’s includes

[Paul Eggert]

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.
* 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.
---
 configure.ac                |  8 --------
 lib-src/emacsclient.c       |  1 +
 lib-src/etags.c             |  4 ----
 lib-src/hexl.c              |  2 ++
 lib-src/make-docfile.c      |  4 ++--
 lib-src/movemail.c          |  2 +-
 lib-src/pop.c               |  2 ++
 lib-src/profile.c           |  1 +
 lib-src/update-game-score.c |  1 -
 lib/openat-die.c            |  1 +
 lwlib/lwlib-Xm.c            |  1 +
 lwlib/lwlib.c               |  1 +
 src/alloc.c                 |  1 +
 src/buffer.c                |  1 +
 src/callproc.c              |  1 +
 src/charset.c               |  1 +
 src/conf_post.h             | 36 ++++++++++++------------------------
 src/dbusbind.c              |  1 +
 src/dispnew.c               |  1 +
 src/doprnt.c                |  1 +
 src/editfns.c               |  1 +
 src/emacs-module.c          |  2 --
 src/emacs.c                 |  1 +
 src/eval.c                  |  1 +
 src/filelock.c              |  1 +
 src/fns.c                   |  1 +
 src/font.c                  |  1 +
 src/fontset.c               |  1 +
 src/frame.c                 |  1 +
 src/keymap.c                |  1 +
 src/lisp.h                  |  2 ++
 src/lread.c                 |  1 +
 src/process.c               |  1 +
 src/regex.c                 | 16 ++--------------
 src/sysdep.c                |  1 +
 src/systty.h                |  1 -
 src/term.c                  |  1 +
 src/unexcw.c                |  1 -
 src/unexmacosx.c            | 14 +++++---------
 src/w32.c                   |  8 ++++----
 src/w32notify.c             |  8 ++++----
 src/w32proc.c               |  8 ++++----
 src/widget.c                |  1 +
 src/xdisp.c                 |  1 +
 src/xfaces.c                |  1 +
 src/xfns.c                  |  1 +
 src/xfont.c                 |  1 +
 src/xgselect.c              |  1 -
 src/xterm.c                 |  1 +
 49 files changed, 71 insertions(+), 80 deletions(-)

diff --git a/configure.ac b/configure.ac
index 6488f90..fe7f132 100644
--- a/configure.ac
+++ b/configure.ac
@@ -4882,14 +4882,6 @@ AC_DEFUN
 		   [Define to the canonical Emacs configuration name.])
 AC_DEFINE_UNQUOTED(EMACS_CONFIG_OPTIONS, "${emacs_config_options}",
 		   [Define to the options passed to configure.])
-AH_TEMPLATE(config_opsysfile, [Some platforms that do not use configure
-  define this to include extra configuration information.])
-
-case $opsys in
-  mingw32)
-    AC_DEFINE(config_opsysfile, <ms-w32.h>, [])
-    ;;
-esac
 
 XMENU_OBJ=
 XOBJ=
diff --git a/lib-src/emacsclient.c b/lib-src/emacsclient.c
index 458519d..59b6ac9 100644
--- a/lib-src/emacsclient.c
+++ b/lib-src/emacsclient.c
@@ -74,6 +74,7 @@ char *w32_getenv (const char *);
 #include <stdarg.h>
 #include <ctype.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <getopt.h>
 #include <unistd.h>
 
diff --git a/lib-src/etags.c b/lib-src/etags.c
index 3620b0f..6fdb063 100644
--- a/lib-src/etags.c
+++ b/lib-src/etags.c
@@ -90,10 +90,6 @@ char pot_etags_version[] = "@(#) pot revision number is 17.38.1.4";
 
 #include <config.h>
 
-#ifndef _GNU_SOURCE
-# define _GNU_SOURCE 1		/* enables some compiler checks on GNU */
-#endif
-
 /* WIN32_NATIVE is for XEmacs.
    MSDOS, WINDOWSNT, DOS_NT are for Emacs. */
 #ifdef WIN32_NATIVE
diff --git a/lib-src/hexl.c b/lib-src/hexl.c
index 9a5ca7e..5bd8579 100644
--- a/lib-src/hexl.c
+++ b/lib-src/hexl.c
@@ -22,6 +22,8 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <config.h>
 
 #include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 #include <ctype.h>
 
 #include <binary-io.h>
diff --git a/lib-src/make-docfile.c b/lib-src/make-docfile.c
index f463f13..9ba9b6e 100644
--- a/lib-src/make-docfile.c
+++ b/lib-src/make-docfile.c
@@ -37,11 +37,11 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <config.h>
 
 #include <stdarg.h>
-#include <stdbool.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
-#include <stdlib.h>   /* config.h unconditionally includes this anyway */
+#include <stdlib.h>
+#include <string.h>
 
 #ifdef WINDOWSNT
 /* Defined to be sys_fopen in ms-w32.h, but only #ifdef emacs, so this
diff --git a/lib-src/movemail.c b/lib-src/movemail.c
index 45779da..8111c87 100644
--- a/lib-src/movemail.c
+++ b/lib-src/movemail.c
@@ -59,8 +59,8 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/file.h>
-#include <stdbool.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <errno.h>
 #include <time.h>
 
diff --git a/lib-src/pop.c b/lib-src/pop.c
index 99ec1cf..99424c5 100644
--- a/lib-src/pop.c
+++ b/lib-src/pop.c
@@ -63,10 +63,12 @@ void sys_freeaddrinfo (struct addrinfo * ai);
 extern struct servent *hes_getservbyname (/* char *, char * */);
 #endif
 
+#include <alloca.h>
 #include <pwd.h>
 #include <netdb.h>
 #include <errno.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 
diff --git a/lib-src/profile.c b/lib-src/profile.c
index 0e60377..edd36ca 100644
--- a/lib-src/profile.c
+++ b/lib-src/profile.c
@@ -35,6 +35,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include <inttypes.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 #include <intprops.h>
 #include <systime.h>
diff --git a/lib-src/update-game-score.c b/lib-src/update-game-score.c
index 7675e9b..7e1b332 100644
--- a/lib-src/update-game-score.c
+++ b/lib-src/update-game-score.c
@@ -37,7 +37,6 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <errno.h>
 #include <inttypes.h>
 #include <limits.h>
-#include <stdbool.h>
 #include <string.h>
 #include <stdlib.h>
 #include <stdio.h>
diff --git a/lib/openat-die.c b/lib/openat-die.c
index f09123e..8dab8b9 100644
--- a/lib/openat-die.c
+++ b/lib/openat-die.c
@@ -2,5 +2,6 @@
    This should never happen with Emacs.  */
 #include <config.h>
 #include "openat.h"
+#include <stdlib.h>
 void openat_save_fail (int errnum) { abort (); }
 void openat_restore_fail (int errnum) { abort (); }
diff --git a/lwlib/lwlib-Xm.c b/lwlib/lwlib-Xm.c
index c92edd2..45faff8 100644
--- a/lwlib/lwlib-Xm.c
+++ b/lwlib/lwlib-Xm.c
@@ -22,6 +22,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include <unistd.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <setjmp.h>
 
 #include <X11/StringDefs.h>
diff --git a/lwlib/lwlib.c b/lwlib/lwlib.c
index d1c5195..e66147f 100644
--- a/lwlib/lwlib.c
+++ b/lwlib/lwlib.c
@@ -26,6 +26,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include <sys/types.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include "lwlib-int.h"
 #include "lwlib-utils.h"
 #include <X11/StringDefs.h>
diff --git a/src/alloc.c b/src/alloc.c
index 41b2f9e..cbfc0dc 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -22,6 +22,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include <errno.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <limits.h>		/* For CHAR_BIT.  */
 #include <signal.h>		/* For SIGABRT, SIGDANGER.  */
 
diff --git a/src/buffer.c b/src/buffer.c
index 24c997f..3d205bb 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -25,6 +25,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <sys/param.h>
 #include <errno.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <unistd.h>
 
 #include <verify.h>
diff --git a/src/callproc.c b/src/callproc.c
index 454ed6d..8ed2855 100644
--- a/src/callproc.c
+++ b/src/callproc.c
@@ -22,6 +22,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <config.h>
 #include <errno.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <sys/types.h>
 #include <unistd.h>
 
diff --git a/src/charset.c b/src/charset.c
index 0c831f1..14d976a 100644
--- a/src/charset.c
+++ b/src/charset.c
@@ -30,6 +30,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include <errno.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <unistd.h>
 #include <limits.h>
 #include <sys/types.h>
diff --git a/src/conf_post.h b/src/conf_post.h
index 6d54524..c0993a3 100644
--- a/src/conf_post.h
+++ b/src/conf_post.h
@@ -18,22 +18,23 @@ GNU General Public License for more details.
 You should have received a copy of the GNU General Public License
 along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 
-/* Commentary:
+/* Put the code here rather than in configure.ac using AH_BOTTOM.
+   This way, the code does not get processed by autoheader.  For
+   example, undefs here are not commented out.
 
-   Rather than writing this code directly in AH_BOTTOM, we include it
-   via this file.  This is so that it does not get processed by
-   autoheader.  Eg, any undefs here would otherwise be commented out.
-*/
+   To help make dependencies clearer elsewhere, this file typically
+   does not #include other files.  The exceptions are first stdbool.h
+   because it is unlikely to interfere with configuration and bool is
+   such a core part of the C language, and second ms-w32.h (DOS_NT
+   only) because it historically was included here and changing that
+   would take some work.  */
 
-/* Code: */
+#include <stdbool.h>
 
-/* Include any platform specific configuration file.  */
-#ifdef config_opsysfile
-# include config_opsysfile
+#if defined DOS_NT && !DEFER_MS_W32_H
+# include <ms-w32.h>
 #endif
 
-#include <stdbool.h>
-
 /* GNUC_PREREQ (V, W, X) is true if this is GNU C version V.W.X or later.
    It can be used in a preprocessor expression.  */
 #ifndef __GNUC_MINOR__
@@ -55,14 +56,6 @@ typedef unsigned int bool_bf;
 typedef bool bool_bf;
 #endif
 
-#ifndef WINDOWSNT
-/* On AIX 3 this must be included before any other include file.  */
-#include <alloca.h>
-#if ! HAVE_ALLOCA
-# error "alloca not available on this machine"
-#endif
-#endif
-
 /* Simulate __has_attribute on compilers that lack it.  It is used only
    on arguments like alloc_size that are handled in this simulation.  */
 #ifndef __has_attribute
@@ -239,9 +232,6 @@ extern void _DebPrint (const char *fmt, ...);
 extern char *emacs_getenv_TZ (void);
 extern int emacs_setenv_TZ (char const *);
 
-#include <string.h>
-#include <stdlib.h>
-
 #if __GNUC__ >= 3  /* On GCC 3.0 we might get a warning.  */
 #define NO_INLINE __attribute__((noinline))
 #else
@@ -365,5 +355,3 @@ extern int emacs_setenv_TZ (char const *);
 #else
 # define UNINIT /* empty */
 #endif
-
-/* conf_post.h ends here */
diff --git a/src/dbusbind.c b/src/dbusbind.c
index 7a94c81..a0146a3 100644
--- a/src/dbusbind.c
+++ b/src/dbusbind.c
@@ -20,6 +20,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #ifdef HAVE_DBUS
 #include <stdio.h>
+#include <stdlib.h>
 #include <dbus/dbus.h>
 
 #include "lisp.h"
diff --git a/src/dispnew.c b/src/dispnew.c
index 82d0b76..70d4de0 100644
--- a/src/dispnew.c
+++ b/src/dispnew.c
@@ -21,6 +21,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <config.h>
 
 #include "sysstdio.h"
+#include <stdlib.h>
 #include <unistd.h>
 
 #include "lisp.h"
diff --git a/src/doprnt.c b/src/doprnt.c
index 9d8b783..44a75f8 100644
--- a/src/doprnt.c
+++ b/src/doprnt.c
@@ -103,6 +103,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include <config.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <float.h>
 #include <unistd.h>
 #include <limits.h>
diff --git a/src/editfns.c b/src/editfns.c
index 835e432..8f6fc80 100644
--- a/src/editfns.c
+++ b/src/editfns.c
@@ -49,6 +49,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <limits.h>
 
 #include <intprops.h>
+#include <stdlib.h>
 #include <strftime.h>
 #include <verify.h>
 
diff --git a/src/emacs-module.c b/src/emacs-module.c
index 724d24a..0535a34 100644
--- a/src/emacs-module.c
+++ b/src/emacs-module.c
@@ -21,11 +21,9 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include "emacs-module.h"
 
-#include <stdbool.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
-#include <string.h>
 
 #include "lisp.h"
 #include "dynlib.h"
diff --git a/src/emacs.c b/src/emacs.c
index 9b23009..13378c4 100644
--- a/src/emacs.c
+++ b/src/emacs.c
@@ -24,6 +24,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <errno.h>
 #include <fcntl.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 #include <sys/types.h>
 #include <sys/file.h>
diff --git a/src/eval.c b/src/eval.c
index e08a25a..abc42a1 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -22,6 +22,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <config.h>
 #include <limits.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include "lisp.h"
 #include "blockinput.h"
 #include "commands.h"
diff --git a/src/filelock.c b/src/filelock.c
index bde34e2..a2e1df9 100644
--- a/src/filelock.c
+++ b/src/filelock.c
@@ -27,6 +27,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <sys/stat.h>
 #include <signal.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 #ifdef HAVE_PWD_H
 #include <pwd.h>
diff --git a/src/fns.c b/src/fns.c
index 31f0fd2..4f12dd5 100644
--- a/src/fns.c
+++ b/src/fns.c
@@ -20,6 +20,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include <config.h>
 
+#include <stdlib.h>
 #include <unistd.h>
 #include <filevercmp.h>
 #include <intprops.h>
diff --git a/src/font.c b/src/font.c
index 144ba07..89f7c8e 100644
--- a/src/font.c
+++ b/src/font.c
@@ -23,6 +23,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <config.h>
 #include <float.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 #include <c-ctype.h>
 
diff --git a/src/fontset.c b/src/fontset.c
index 67696d0..fe595d8 100644
--- a/src/fontset.c
+++ b/src/fontset.c
@@ -26,6 +26,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include <config.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 #include "lisp.h"
 #include "blockinput.h"
diff --git a/src/frame.c b/src/frame.c
index 166623c..8831b9a 100644
--- a/src/frame.c
+++ b/src/frame.c
@@ -20,6 +20,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <config.h>
 
 #include <stdio.h>
+#include <stdlib.h>
 #include <errno.h>
 #include <limits.h>
 
diff --git a/src/keymap.c b/src/keymap.c
index b27df1d..c4a59ad 100644
--- a/src/keymap.c
+++ b/src/keymap.c
@@ -41,6 +41,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include <config.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 #include "lisp.h"
 #include "commands.h"
diff --git a/src/lisp.h b/src/lisp.h
index f653d85..7430898 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -21,10 +21,12 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #ifndef EMACS_LISP_H
 #define EMACS_LISP_H
 
+#include <alloca.h>
 #include <setjmp.h>
 #include <stdalign.h>
 #include <stdarg.h>
 #include <stddef.h>
+#include <string.h>
 #include <float.h>
 #include <inttypes.h>
 #include <limits.h>
diff --git a/src/lread.c b/src/lread.c
index dc7c00b..d5e0460 100644
--- a/src/lread.c
+++ b/src/lread.c
@@ -23,6 +23,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include <config.h>
 #include "sysstdio.h"
+#include <stdlib.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/file.h>
diff --git a/src/process.c b/src/process.c
index 29bf43e..d77c5bf 100644
--- a/src/process.c
+++ b/src/process.c
@@ -22,6 +22,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <config.h>
 
 #include <stdio.h>
+#include <stdlib.h>
 #include <errno.h>
 #include <sys/types.h>		/* Some typedefs are used in sys/file.h.  */
 #include <sys/file.h>
diff --git a/src/regex.c b/src/regex.c
index 41c1d3f..1917a84 100644
--- a/src/regex.c
+++ b/src/regex.c
@@ -50,6 +50,7 @@
 #include <config.h>
 
 #include <stddef.h>
+#include <stdlib.h>
 
 #ifdef emacs
 /* We need this for `regex.h', and perhaps for the Emacs include files.  */
@@ -443,25 +444,12 @@ init_syntax_once (void)
 
 #else /* not REGEX_MALLOC  */
 
-/* Emacs already defines alloca, sometimes.  */
-# ifndef alloca
-
-/* Make alloca work the best possible way.  */
-#  ifdef __GNUC__
-#   define alloca __builtin_alloca
-#  else /* not __GNUC__ */
-#   ifdef HAVE_ALLOCA_H
-#    include <alloca.h>
-#   endif /* HAVE_ALLOCA_H */
-#  endif /* not __GNUC__ */
-
-# endif /* not alloca */
-
 # ifdef emacs
 #  define REGEX_USE_SAFE_ALLOCA USE_SAFE_ALLOCA
 #  define REGEX_SAFE_FREE() SAFE_FREE ()
 #  define REGEX_ALLOCATE SAFE_ALLOCA
 # else
+#  include <alloca.h>
 #  define REGEX_ALLOCATE alloca
 # endif
 
diff --git a/src/sysdep.c b/src/sysdep.c
index 190d6fbe..0121f01 100644
--- a/src/sysdep.c
+++ b/src/sysdep.c
@@ -26,6 +26,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <grp.h>
 #endif /* HAVE_PWD_H */
 #include <limits.h>
+#include <stdlib.h>
 #include <unistd.h>
 
 #include <c-ctype.h>
diff --git a/src/systty.h b/src/systty.h
index fbdc6b1..a53c874 100644
--- a/src/systty.h
+++ b/src/systty.h
@@ -26,7 +26,6 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <fcntl.h>
 #endif /* not DOS_NT */
 
-#include <stdbool.h>
 #include <sys/ioctl.h>
 
 #ifdef HPUX
diff --git a/src/term.c b/src/term.c
index c22d07a..d691a7a 100644
--- a/src/term.c
+++ b/src/term.c
@@ -23,6 +23,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <errno.h>
 #include <fcntl.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <sys/file.h>
 #include <sys/time.h>
 #include <unistd.h>
diff --git a/src/unexcw.c b/src/unexcw.c
index 6343b38..c0d1bc1 100644
--- a/src/unexcw.c
+++ b/src/unexcw.c
@@ -21,7 +21,6 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <config.h>
 #include "unexec.h"
 #include "lisp.h"
-#include <string.h>
 #include <stdio.h>
 #include <fcntl.h>
 #include <a.out.h>
diff --git a/src/unexmacosx.c b/src/unexmacosx.c
index 185a9d1..ea8e884 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"
 
diff --git a/src/w32.c b/src/w32.c
index 6cb8e74..e0a3406 100644
--- a/src/w32.c
+++ b/src/w32.c
@@ -21,8 +21,8 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
    Geoff Voelker (voelker@cs.washington.edu)                         7-29-94
 */
 
-/* Enable GNU extensions in gnulib replacement headers.  */
-#define _GNU_SOURCE 1
+#define DEFER_MS_W32_H
+#include <config.h>
 
 #include <mingw_time.h>
 #include <stddef.h> /* for offsetof */
@@ -40,9 +40,9 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <sys/utime.h>
 #include <math.h>
 
-/* must include CRT headers *before* config.h */
+/* Include CRT headers *before* ms-w32.h.  */
+#include <ms-w32.h>
 
-#include <config.h>
 #include <mbstring.h>	/* for _mbspbrk, _mbslwr, _mbsrchr, ... */
 
 #undef access
diff --git a/src/w32notify.c b/src/w32notify.c
index 15e8a86..32a03f7 100644
--- a/src/w32notify.c
+++ b/src/w32notify.c
@@ -81,14 +81,14 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
    thread to exit.  The main thread waits for some time for the worker
    thread to exit, and if it doesn't, terminates it forcibly.  */
 
-/* Enable GNU extensions in gnulib replacement headers.  */
-#define _GNU_SOURCE 1
+#define DEFER_MS_W32_H
+#include <config.h>
 
 #include <stddef.h>
 #include <errno.h>
 
-/* must include CRT headers *before* config.h */
-#include <config.h>
+/* Include CRT headers *before* ms-w32.h.  */
+#include <ms-w32.h>
 
 #include <windows.h>
 
diff --git a/src/w32proc.c b/src/w32proc.c
index e23b1b3..aef4e44 100644
--- a/src/w32proc.c
+++ b/src/w32proc.c
@@ -22,8 +22,8 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
      Adapted from alarm.c by Tim Fleehart
 */
 
-/* Enable GNU extensions in gnulib replacement headers.  */
-#define _GNU_SOURCE 1
+#define DEFER_MS_W32_H
+#include <config.h>
 
 #include <mingw_time.h>
 #include <stdio.h>
@@ -38,8 +38,8 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <mbstring.h>
 #include <locale.h>
 
-/* must include CRT headers *before* config.h */
-#include <config.h>
+/* Include CRT headers *before* ms-w32.h.  */
+#include <ms-w32.h>
 
 #undef signal
 #undef wait
diff --git a/src/widget.c b/src/widget.c
index 28bb475..59ed431 100644
--- a/src/widget.c
+++ b/src/widget.c
@@ -32,6 +32,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include "widget.h"
 
 #include <stdio.h>
+#include <stdlib.h>
 
 #include "lisp.h"
 #include "xterm.h"
diff --git a/src/xdisp.c b/src/xdisp.c
index 4bf1470..67d14c8 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -288,6 +288,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include <config.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <limits.h>
 
 #include "lisp.h"
diff --git a/src/xfaces.c b/src/xfaces.c
index 056f90c..5837f35 100644
--- a/src/xfaces.c
+++ b/src/xfaces.c
@@ -200,6 +200,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
    used to fill in unspecified attributes of the default face.  */
 
 #include <config.h>
+#include <stdlib.h>
 #include "sysstdio.h"
 #include <sys/types.h>
 #include <sys/stat.h>
diff --git a/src/xfns.c b/src/xfns.c
index dd39e78..8571d0e 100644
--- a/src/xfns.c
+++ b/src/xfns.c
@@ -19,6 +19,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include <config.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <math.h>
 #include <unistd.h>
 
diff --git a/src/xfont.c b/src/xfont.c
index 8fbe94c..45b0e0a 100644
--- a/src/xfont.c
+++ b/src/xfont.c
@@ -21,6 +21,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include <config.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <X11/Xlib.h>
 
 #include "lisp.h"
diff --git a/src/xgselect.c b/src/xgselect.c
index ac88afd..7850a16 100644
--- a/src/xgselect.c
+++ b/src/xgselect.c
@@ -25,7 +25,6 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include <glib.h>
 #include <errno.h>
-#include <stdbool.h>
 #include "blockinput.h"
 #include "systime.h"
 
diff --git a/src/xterm.c b/src/xterm.c
index 4c14e62..7476694 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -22,6 +22,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include <config.h>
 #include <stdio.h>
+#include <stdlib.h>
 #ifdef USE_CAIRO
 #include <math.h>
 #endif
-- 
2.7.4

bug#24506: Limit <config.h>’s includes

[Andy Moreton]

On Thu 22 Sep 2016, Paul Eggert wrote:

> 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.

The check at the top of src/conf_post.h needs a minor fix:

#if defined DOS_NT && !defined DEFER_MS_W32_H

After that, it bootstraps on Windows using 64bit MSYS2 (gcc 6.2.0) and
appears to be functional.

    AndyM

bug#24506: Limit <config.h>’s includes

[Paul Eggert]

Thanks for checking it on MSYS2. I made the change you suggested, 
installed the resulting patch, and am marking this as done.

In <http://lists.gnu.org/archive/html/emacs-devel/2016-09/msg00640.html> 
I proposed also changing conf_post.h to conf-post.h as per the usual GNU 
file name conventions. I'll wait a bit on this, as I want to shake out 
any problems with the main patch first.