[PATCH] stdlib: support including stdlib.h from config.h

[Paul Eggert]

Emacs <config.h> includes <stdlib.h> in some situations, causing
problems on macOS as described by Eli Zaretskii in:
https://lists.gnu.org/r/emacs-devel/2024-12/msg00923.html
Although this usage is not recommended, it is easier to support
it for POSIX-required headers, than to fix Emacs.
* doc/extern-inline.texi (extern inline): Document the Emacs problem.
* lib/endian.c, lib/math.c, lib/stdbit.c, lib/stdlib.c:
* lib/sys_socket.c, lib/unistd.c, lib/wctype-h.c:
Define #define _GL_..._INLINE to _GL_EXTERN_INLINE
before including <config.h>, not merely before including
the .h file that defines the inline function.
---
 ChangeLog              | 15 +++++++++++++++
 doc/extern-inline.texi |  8 +++++++-
 lib/endian.c           |  2 +-
 lib/math.c             |  2 +-
 lib/stdbit.c           |  2 +-
 lib/stdlib.c           |  2 +-
 lib/sys_socket.c       |  2 +-
 lib/unistd.c           |  2 +-
 lib/wctype-h.c         |  2 +-
 9 files changed, 29 insertions(+), 8 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 38b95c2479..2a60634dc0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,18 @@
+2024-12-24  Paul Eggert  <eggert@cs.ucla.edu>
+
+       stdlib: support including stdlib.h from config.h
+       Emacs <config.h> includes <stdlib.h> in some situations, causing
+       problems on macOS as described by Eli Zaretskii in:
+       https://lists.gnu.org/r/emacs-devel/2024-12/msg00923.html
+       Although this usage is not recommended, it is easier to support
+       it for POSIX-required headers, than to fix Emacs.
+       * doc/extern-inline.texi (extern inline): Document the Emacs problem.
+       * lib/endian.c, lib/math.c, lib/stdbit.c, lib/stdlib.c:
+       * lib/sys_socket.c, lib/unistd.c, lib/wctype-h.c:
+       Define #define _GL_..._INLINE to _GL_EXTERN_INLINE
+       before including <config.h>, not merely before including
+       the .h file that defines the inline function.
+
 2024-12-24  Bruno Haible  <bruno@clisp.org>
 
        setlocale: Fix a buffer overflow check (mistake in yesterday's commit).
diff --git a/doc/extern-inline.texi b/doc/extern-inline.texi
index 3ebc39cdac..87b76f6451 100644
--- a/doc/extern-inline.texi
+++ b/doc/extern-inline.texi
@@ -67,8 +67,8 @@ and @file{aaa.c} can do this:
 
 @example
 /* aaa.c */
-#include <config.h>
 #define AAA_INLINE _GL_EXTERN_INLINE
+#include <config.h>
 #include <aaa.h>
 @end example
 
@@ -83,6 +83,12 @@ inline} so they suffer from code bloat, but they are not 
mainline
 platforms and will die out eventually.
 
 In this coding idiom,
+the compilation unit should define @code{AAA_INLINE} before
+including the @file{aaa.h} header that conditionally defines it.
+In the unusual and not-recommended case where @file{config.h}
+itself includes @file{aaa.h}, the compilation unit should
+define @code{AAA_INLINE} before including @file{config.h},
+not merely before including @file{aaa.h}.  Also,
 you need one @code{AAA_INLINE}-like macro per compilation unit,
 not one per header file.
 In other words, if the header file @file{aaa.h} defines functions
diff --git a/lib/endian.c b/lib/endian.c
index 3e7e56f523..089f5f7825 100644
--- a/lib/endian.c
+++ b/lib/endian.c
@@ -17,7 +17,7 @@
 
 /* Written by Collin Funk.  */
 
+#define _GL_ENDIAN_INLINE _GL_EXTERN_INLINE
 #include <config.h>
 
-#define _GL_ENDIAN_INLINE _GL_EXTERN_INLINE
 #include <endian.h>
diff --git a/lib/math.c b/lib/math.c
index 78da4d4aca..ade0d2657c 100644
--- a/lib/math.c
+++ b/lib/math.c
@@ -15,8 +15,8 @@
    You should have received a copy of the GNU Lesser General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
 
+#define _GL_MATH_INLINE _GL_EXTERN_INLINE
 #include <config.h>
 
-#define _GL_MATH_INLINE _GL_EXTERN_INLINE
 #include <math.h>
 typedef int dummy;
diff --git a/lib/stdbit.c b/lib/stdbit.c
index 4801e74d28..b9c52698e9 100644
--- a/lib/stdbit.c
+++ b/lib/stdbit.c
@@ -17,7 +17,7 @@
 
 /* Written by Paul Eggert.  */
 
+#define _GL_STDBIT_INLINE _GL_EXTERN_INLINE
 #include <config.h>
 
-#define _GL_STDBIT_INLINE _GL_EXTERN_INLINE
 #include <stdbit.h>
diff --git a/lib/stdlib.c b/lib/stdlib.c
index 521d64627d..6f70fa4bbd 100644
--- a/lib/stdlib.c
+++ b/lib/stdlib.c
@@ -15,7 +15,7 @@
    You should have received a copy of the GNU Lesser General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
 
+#define _GL_STDLIB_INLINE _GL_EXTERN_INLINE
 #include <config.h>
 
-#define _GL_STDLIB_INLINE _GL_EXTERN_INLINE
 #include <stdlib.h>
diff --git a/lib/sys_socket.c b/lib/sys_socket.c
index 672d3aace6..49d2122da5 100644
--- a/lib/sys_socket.c
+++ b/lib/sys_socket.c
@@ -15,8 +15,8 @@
    You should have received a copy of the GNU Lesser General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
 
+#define _GL_SYS_SOCKET_INLINE _GL_EXTERN_INLINE
 #include <config.h>
 
-#define _GL_SYS_SOCKET_INLINE _GL_EXTERN_INLINE
 #include <sys/socket.h>
 typedef int dummy;
diff --git a/lib/unistd.c b/lib/unistd.c
index f3b3f7bd2f..b25112eb91 100644
--- a/lib/unistd.c
+++ b/lib/unistd.c
@@ -15,8 +15,8 @@
    You should have received a copy of the GNU Lesser General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
 
+#define _GL_UNISTD_INLINE _GL_EXTERN_INLINE
 #include <config.h>
 
-#define _GL_UNISTD_INLINE _GL_EXTERN_INLINE
 #include <unistd.h>
 typedef int dummy;
diff --git a/lib/wctype-h.c b/lib/wctype-h.c
index 7e4ff13a71..a1f020fd65 100644
--- a/lib/wctype-h.c
+++ b/lib/wctype-h.c
@@ -17,7 +17,7 @@
 
 /* Normally this would be wctype.c, but that name's already taken.  */
 
+#define _GL_WCTYPE_INLINE _GL_EXTERN_INLINE
 #include <config.h>
 
-#define _GL_WCTYPE_INLINE _GL_EXTERN_INLINE
 #include <wctype.h>
-- 
2.45.2