warn-on-use: use instead of link-warning

Each *.in.h file serves two purposes - provide enough self-contained
content to serve as a replacement for the system header regardless of
the user's compiler, and offer the developer the ability to detect any
gnulib modules that might have been inadvertantly excluded.  The
former requires independence from config.h, and routes everything
through a Makefile.am snippet that uses @@ substitution specific to
the modules that were in use, with details learned at configure time.

The latter works by poisoning anything that gnulib did not replace,
but which the developer had natively available, explaining why their
tests passed during development.  Poisoning relies on gcc features,
and requires manual triggering by adding -DGNULIB_POSIXCHECK to
CFLAGS; it assumes that <config.h> is properly included.  In fact, we
do not want to use @@ substitution for HAVE_DECL_* during poisoning,
because the warning is only relevant for the gnulib modules which were
not included, and thus where the m4 macros to set proper @@ values
have not been run.  Furthermore, we only need to poison interfaces
that already have a declaration; if something is not declared, then
the developer wouldn't have been able to link, so their code won't be
using the problematic interface in the first place.

* modules/stdio (Depends-on, Makefile.am): Drop link-warning.
* modules/unistd (Depends-on, Makefile.am): Likewise.
* modules/arpa_inet (Depends-on): Replace link-warning with
warn-on-use.
(Makefile.am): Update rules accordingly.
* modules/ctype (Depends-on, Makefile.am): Likewise.
* modules/dirent (Depends-on, Makefile.am): Likewise.
* modules/fcntl-h (Depends-on, Makefile.am): Likewise.
* modules/inttypes (Depends-on, Makefile.am): Likewise.
* modules/langinfo (Depends-on, Makefile.am): Likewise.
* modules/locale (Depends-on, Makefile.am): Likewise.
* modules/math (Depends-on, Makefile.am): Likewise.
* modules/search (Depends-on, Makefile.am): Likewise.
* modules/signal (Depends-on, Makefile.am): Likewise.
* modules/spawn (Depends-on, Makefile.am): Likewise.
* modules/stdlib (Depends-on, Makefile.am): Likewise.
* modules/string (Depends-on, Makefile.am): Likewise.
* modules/strings (Depends-on, Makefile.am): Likewise.
* modules/sys_file (Depends-on, Makefile.am): Likewise.
* modules/sys_ioctl (Depends-on, Makefile.am): Likewise.
* modules/sys_select (Depends-on, Makefile.am): Likewise.
* modules/sys_socket (Depends-on, Makefile.am): Likewise.
* modules/sys_stat (Depends-on, Makefile.am): Likewise.
* modules/sys_times (Depends-on, Makefile.am): Likewise.
* modules/sys_utsname (Depends-on, Makefile.am): Likewise.
* modules/wchar (Depends-on, Makefile.am): Likewise.
* m4/arpa_inet_h.m4 (gl_HEADER_ARPA_INET): Check which functions
should be poisoned.
* m4/ctype.m4 (gl_CTYPE_H): Likewise.
* m4/dirent_h.m4 (gl_DIRENT_H): Likewise.
* m4/fcntl_h.m4 (gl_FCNTL_H): Likewise.
* m4/inttypes.m4 (gl_INTTYPES_H): Likewise.
* m4/langinfo_h.m4 (gl_LANGINFO_H): Likewise.
* m4/locale_h.m4 (gl_LOCALE_H): Likewise.
* m4/math_h.m4 (gl_MATH_H): Likewise.
* m4/search_h.m4 (gl_SEARCH_H): Likewise.
* m4/signal_h.m4 (gl_SIGNAL_H): Likewise.
* m4/spawn_h.m4 (gl_SPAWN_H): Likewise.
* m4/stdio_h.m4 (gl_STDIO_H): Likewise.
* m4/stdlib_h.m4 (gl_STDLIB_H): Likewise.
* m4/string_h.m4 (gl_HEADER_STRING_H_BODY): Likewise.
* m4/strings_h.m4 (gl_HEADER_STRINGS_H_BODY): Likewise.
* m4/sys_file_h.m4 (gl_HEADER_SYS_FILE_H_DEFAULTS): Likewise.
* m4/sys_ioctl_h.m4 (gl_SYS_IOCTL_H): Likewise.
* m4/sys_select_h.m4 (gl_HEADER_SYS_SELECT): Likewise.
* m4/sys_socket_h.m4 (gl_HEADER_SYS_SOCKET): Likewise.
* m4/sys_stat_h.m4 (gl_HEADER_SYS_STAT_H): Likewise.
* m4/sys_times_h.m4 (gl_SYS_TIMES_H): Likewise.
* m4/sys_utsname_h.m4 (gl_SYS_UTSNAME_H): Likewise.
* m4/unistd_h.m4 (gl_UNISTD_H): Likewise.
* m4/wchar.m4 (gl_WCHAR_H): Likewise.
* lib/arpa_inet.in.h: Use _GL_WARN_ON_USE instead of
GL_LINK_WARNING.
* lib/ctype.in.h: Likewise.
* lib/dirent.in.h: Likewise.
* lib/fcntl.in.h: Likewise.
* lib/inttypes.in.h: Likewise.
* lib/langinfo.in.h: Likewise.
* lib/locale.in.h: Likewise.
* lib/math.in.h: Likewise.
* lib/search.in.h: Likewise.
* lib/signal.in.h: Likewise.
* lib/spawn.in.h: Likewise.
* lib/stdio.in.h: Likewise.
* lib/stdlib.in.h: Likewise.
* lib/string.in.h: Likewise.
* lib/strings.in.h: Likewise.
* lib/sys_file.in.h: Likewise.
* lib/sys_ioctl.in.h: Likewise.
* lib/sys_select.in.h: Likewise.
* lib/sys_socket.in.h: Likewise.
* lib/sys_stat.in.h: Likewise.
* lib/sys_times.in.h: Likewise.
* lib/sys_utsname.in.h: Likewise.
* lib/unistd.in.h: Likewise.
* lib/wchar.in.h: Likewise.

Signed-off-by: Eric Blake <ebb9@byu.net>

1 files changed, 18 insertions, 18 deletions

diff --git a/lib/inttypes.in.h b/lib/inttypes.in.h
index 14c2b20523..a732c697cd 100644
--- a/lib/inttypes.in.h
+++ b/lib/inttypes.in.h
@@ -48,10 +48,10 @@
 # error "This file assumes that 'int' has exactly 32 bits. Please report your platform and compiler to <bug-gnulib@gnu.org>."
 #endif
 
-/* The definition of GL_LINK_WARNING is copied here.  */
-
 /* The definition of _GL_ARG_NONNULL is copied here.  */
 
+/* The definition of _GL_WARN_ON_USE is copied here.  */
+
 /* 7.8.1 Macros for format specifiers */
 
 #if ! defined __cplusplus || defined __STDC_FORMAT_MACROS
@@ -1050,10 +1050,10 @@ extern intmax_t imaxabs (intmax_t);
 # endif
 #elif defined GNULIB_POSIXCHECK
 # undef imaxabs
-# define imaxabs(a) \
-    (GL_LINK_WARNING ("imaxabs is unportable - " \
-                      "use gnulib module imaxabs for portability"), \
-     imaxabs (a))
+# if HAVE_RAW_DECL_IMAXABS
+_GL_WARN_ON_USE (imaxabs, "imaxabs is unportable - "
+                 "use gnulib module imaxabs for portability");
+# endif
 #endif
 
 #if @GNULIB_IMAXDIV@
@@ -1063,10 +1063,10 @@ extern imaxdiv_t imaxdiv (intmax_t, intmax_t);
 # endif
 #elif defined GNULIB_POSIXCHECK
 # undef imaxdiv
-# define imaxdiv(a,b) \
-    (GL_LINK_WARNING ("imaxdiv is unportable - " \
-                      "use gnulib module imaxdiv for portability"), \
-     imaxdiv (a, b))
+# if HAVE_RAW_DECL_IMAXDIV
+_GL_WARN_ON_USE (imaxdiv, "imaxdiv is unportable - "
+                 "use gnulib module imaxdiv for portability");
+# endif
 #endif
 
 #if @GNULIB_STRTOIMAX@
@@ -1075,10 +1075,10 @@ extern intmax_t strtoimax (const char *, char **, int) _GL_ARG_NONNULL ((1));
 # endif
 #elif defined GNULIB_POSIXCHECK
 # undef strtoimax
-# define strtoimax(p,e,b) \
-    (GL_LINK_WARNING ("strtoimax is unportable - " \
-                      "use gnulib module strtoimax for portability"), \
-     strtoimax (p, e, b))
+# if HAVE_RAW_DECL_STRTOIMAX
+_GL_WARN_ON_USE (strtoimax, "strtoimax is unportable - "
+                 "use gnulib module strtoimax for portability");
+# endif
 #endif
 
 #if @GNULIB_STRTOUMAX@
@@ -1087,10 +1087,10 @@ extern uintmax_t strtoumax (const char *, char **, int) _GL_ARG_NONNULL ((1));
 # endif
 #elif defined GNULIB_POSIXCHECK
 # undef strtoumax
-# define strtoumax(p,e,b) \
-    (GL_LINK_WARNING ("strtoumax is unportable - " \
-                      "use gnulib module strtoumax for portability"), \
-     strtoumax (p, e, b))
+# if HAVE_RAW_DECL_STRTOUMAX
+_GL_WARN_ON_USE (strtoumax, "strtoumax is unportable - "
+                 "use gnulib module strtoumax for portability");
+# endif
 #endif
 
 /* Don't bother defining or declaring wcstoimax and wcstoumax, since