stddef: fix NetBSD 5.0 NULL bug, rather than working around it

* tests/test-locale.c: Revert previous patch related to NULL.
* tests/test-stdio.c: Likewise.
* tests/test-stdlib.c: Likewise.
* tests/test-string.c: Likewise.
* tests/test-unistd.c: Likewise.
* modules/time-tests (Depends-on): Add verify.
* modules/wchar-tests (Depends-on): Likewise.
* tests/test-time.c: Test for NULL compliance.
* tests/test-wchar.c: Likewise.
* modules/locale (Depends-on): Add stddef.
* modules/stdio (Depends-on): Likewise.
* modules/stdlib (Depends-on): Likewise.
* modules/string (Depends-on): Likewise.
* modules/time (Depends-on): Likewise.
* modules/unistd (Depends-on): Likewise.
* modules/wchar (Depends-on): Likewise.
* lib/locale.in.h (includes): Use <stddef.h> to fix NULL.
* lib/stdlib.in.h (includes): Likewise.
* lib/string.in.h (includes): Likewise.
* lib/time.in.h (includes): Likewise.
* lib/unistd.in.h (includes): Likewise.
* m4/locale_h.m4 (gl_LOCALE_H): Replace locale.h if stddef.h was
replaced.
* m4/wchar.m4 (gl_WCHAR_H): Likewise.
* m4/stddef_h.m4: New file.
* modules/stddef: Likewise.
* lib/stddef.in.h: Likewise.
* modules/stddef-tests: Likewise.
* tests/test-stddef.c: Likewise.
* MODULES.html.sh (Basic types <stddef.h>): Mention new module.
* doc/posix-headers/stddef.texi (stddef.h): Document the bug.
* doc/posix-headers/locale.texi (locale.h): Likewise.
* doc/posix-headers/stdio.texi (stdio.h): Likewise.
* doc/posix-headers/stdlib.texi (stdlib.h): Likewise.
* doc/posix-headers/string.texi (string.h): Likewise.
* doc/posix-headers/time.texi (time.h): Likewise.
* doc/posix-headers/unistd.texi (unistd.h): Likewise.
* doc/posix-headers/wchar.texi (wchar.h): Likewise.

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

6 files changed, 100 insertions, 3 deletions

diff --git a/lib/locale.in.h b/lib/locale.in.h
index 10629f6c79..0557c9f170 100644
--- a/lib/locale.in.h
+++ b/lib/locale.in.h
@@ -1,5 +1,5 @@
 /* A POSIX <locale.h>.
-   Copyright (C) 2007-2008 Free Software Foundation, Inc.
+   Copyright (C) 2007-2009 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -26,6 +26,9 @@
 #ifndef _GL_LOCALE_H
 #define _GL_LOCALE_H
 
+/* NetBSD 5.0 mis-defines NULL.  */
+#include <stddef.h>
+
 /* The LC_MESSAGES locale category is specified in POSIX, but not in ISO C.
    On systems that don't define it, use the same value as GNU libintl.  */
 #if !defined LC_MESSAGES
diff --git a/lib/stddef.in.h b/lib/stddef.in.h
new file mode 100644
index 0000000000..8744207944
--- /dev/null
+++ b/lib/stddef.in.h
@@ -0,0 +1,86 @@
+/* A substitute for POSIX 2008 <stddef.h>, for platforms that have issues.
+
+   Copyright (C) 2009 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+/* Written by Eric Blake.  */
+
+/*
+ * POSIX 2008 <stddef.h> for platforms that have issues.
+ * <http://www.opengroup.org/susv3xbd/stddef.h.html>
+ */
+
+#if __GNUC__ >= 3
+@PRAGMA_SYSTEM_HEADER@
+#endif
+
+#if defined __need_wchar_t || defined __need_size_t  \
+  || defined __need_ptrdiff_t || defined __need_NULL \
+  || defined __need_wint_t
+/* Special invocation convention inside gcc header files.  In
+   particular, gcc provides a version of <stddef.h> that blindly
+   redefines NULL even when __need_wint_t was defined, even though
+   wint_t is not normally provided by <stddef.h>.  Hence, we must
+   remember if special invocation has ever been used to obtain wint_t,
+   in which case we need to clean up NULL yet again.  */
+
+# if !(defined _GL_STDDEF_H && defined _GL_STDDEF_WINT_T)
+#  ifdef __need_wint_t
+#   undef _GL_STDDEF_H
+#   define _GL_STDDEF_WINT_T
+#  endif
+#  @INCLUDE_NEXT@ @NEXT_STDDEF_H@
+# endif
+
+#else
+/* Normal invocation convention.  */
+
+# ifndef _GL_STDDEF_H
+
+/* The include_next requires a split double-inclusion guard.  */
+
+#  @INCLUDE_NEXT@ @NEXT_STDDEF_H@
+
+#  ifndef _GL_STDDEF_H
+#   define _GL_STDDEF_H
+
+/* On NetBSD 5.0, the definition of NULL lacks proper parentheses.  */
+#if @REPLACE_NULL@
+# undef NULL
+# ifdef __cplusplus
+   /* ISO C++ says that the macro NULL must expand to an integer constant
+      expression, hence '((void *) 0)' is not allowed in C++.  */
+#  if __GNUG__ >= 3
+    /* GNU C++ has a __null macro that behaves like an integer ('int' or
+       'long') but has the same size as a pointer.  Use that, to avoid
+       warnings.  */
+#   define NULL __null
+#  else
+#   define NULL 0L
+#  endif
+# else
+#  define NULL ((void *) 0)
+# endif
+#endif
+
+/* Some platforms lack wchar_t.  */
+#if !@HAVE_WCHAR_T@
+# define wchar_t int
+#endif
+
+#  endif /* _GL_STDDEF_H */
+# endif /* _GL_STDDEF_H */
+#endif /* __need_XXX */
diff --git a/lib/stdlib.in.h b/lib/stdlib.in.h
index f99767f600..c7c8e8fb7f 100644
--- a/lib/stdlib.in.h
+++ b/lib/stdlib.in.h
@@ -35,6 +35,8 @@
 #ifndef _GL_STDLIB_H
 #define _GL_STDLIB_H
 
+/* NetBSD 5.0 mis-defines NULL.  */
+#include <stddef.h>
 
 /* Solaris declares getloadavg() in <sys/loadavg.h>.  */
 #if @GNULIB_GETLOADAVG@ && @HAVE_SYS_LOADAVG_H@
diff --git a/lib/string.in.h b/lib/string.in.h
index 9f98b0df97..8eaeeb8824 100644
--- a/lib/string.in.h
+++ b/lib/string.in.h
@@ -28,6 +28,8 @@
 #ifndef _GL_STRING_H
 #define _GL_STRING_H
 
+/* NetBSD 5.0 mis-defines NULL.  */
+#include <stddef.h>
 
 #ifndef __attribute__
 /* This feature is available in gcc versions 2.5 and later.  */
diff --git a/lib/time.in.h b/lib/time.in.h
index b9c2230d6e..e8e7c197f6 100644
--- a/lib/time.in.h
+++ b/lib/time.in.h
@@ -37,6 +37,9 @@
 
 # @INCLUDE_NEXT@ @NEXT_TIME_H@
 
+/* NetBSD 5.0 mis-defines NULL.  */
+#include <stddef.h>
+
 # ifdef __cplusplus
 extern "C" {
 # endif
diff --git a/lib/unistd.in.h b/lib/unistd.in.h
index 5cad6c8ad9..7696178799 100644
--- a/lib/unistd.in.h
+++ b/lib/unistd.in.h
@@ -29,6 +29,9 @@
 #ifndef _GL_UNISTD_H
 #define _GL_UNISTD_H
 
+/* NetBSD 5.0 mis-defines NULL.  Also get size_t.  */
+#include <stddef.h>
+
 /* mingw doesn't define the SEEK_* or *_FILENO macros in <unistd.h>.  */
 #if !(defined SEEK_CUR && defined SEEK_END && defined SEEK_SET)
 # include <stdio.h>
@@ -375,7 +378,6 @@ extern int gethostname(char *name, size_t len);
    See <http://www.opengroup.org/susv3xsh/getlogin.html>.
  */
 # if !@HAVE_DECL_GETLOGIN_R@
-#  include <stddef.h>
 extern int getlogin_r (char *name, size_t size);
 # endif
 #elif defined GNULIB_POSIXCHECK
@@ -536,7 +538,6 @@ extern int link (const char *path1, const char *path2);
    See the POSIX:2001 specification
    <http://www.opengroup.org/susv3xsh/readlink.html>.  */
 # if !@HAVE_READLINK@
-#  include <stddef.h>
 extern int readlink (const char *file, char *buf, size_t bufsize);
 # endif
 #elif defined GNULIB_POSIXCHECK