_AC_PROG_CXX_EXIT_DECLARATION: don't `#include <stdlib.h>'

[Jim Meyering]

If anyone knows of a system on which <stdlib.h> (or any other header)
should be included from confdefs.h (later known as config.h),
please speak up now.

This change makes it so that when running configure with e.g., CC=aCC,
you'll now get this in confdefs.h:

  #ifdef __cplusplus
  extern "C" void exit (int);
  #endif

rather than this:

  #ifdef __cplusplus
  #include <stdlib.h>
  #endif

which would cause things like AC_REPLACE_FUNCS(getopt)
mistakenly to replace getopt on systems that already provide it.

Jim


2003-05-22  Jim Meyering  <address@hidden>

        * lib/autoconf/c.m4 (_AC_PROG_CXX_EXIT_DECLARATION): Remove
        `#include <stdlib.h>' from the list;  we should never make
        confdefs.h include <stdlib.h> or <cstdlib>, because the resulting
        namespace pollution would cause other tests to fail.  Configure scripts
        run with some older versions of g++ and HP's aCC would fail due to
        such an #include.  Reports here http://bugs.debian.org/120704 and
        here http://mail.gnu.org/archive/html/autoconf/2003-05/msg00063.html.

Index: lib/autoconf/c.m4
===================================================================
RCS file: /cvsroot/autoconf/autoconf/lib/autoconf/c.m4,v
retrieving revision 1.177
diff -u -p -u -5 -r1.177 c.m4
--- lib/autoconf/c.m4   14 Apr 2003 03:47:30 -0000      1.177
+++ lib/autoconf/c.m4   22 May 2003 15:57:12 -0000
@@ -721,15 +721,15 @@ fi[]dnl
 ])# _AC_PROG_CXX_G
 
 
 # _AC_PROG_CXX_EXIT_DECLARATION
 # -----------------------------
-# Find a valid prototype for exit and declare it in confdefs.h.
+# If <stdlib.h> doesn't already provide a valid prototype for exit,
+# determine the appropriate prototype and put it in confdefs.h.
 m4_define([_AC_PROG_CXX_EXIT_DECLARATION],
 [for ac_declaration in \
    ''\
-   '#include <stdlib.h>' \
    'extern "C" void std::exit (int) throw (); using std::exit;' \
    'extern "C" void std::exit (int); using std::exit;' \
    'extern "C" void exit (int) throw ();' \
    'extern "C" void exit (int);' \
    'void exit (int);'