autoconfig 2.62, config.h, and __EXTENSIONS__

[David Reiser]

autoconfig 2.62 creates a configure file containing a section of about  
300 lines that does not appear using autoconfig 2.60. This new section  
contains:

   { $as_echo "$as_me:$LINENO: checking whether it is safe to define  
__EXTENSIONS__" >&5
$as_echo_n "checking whether it is safe to define __EXTENSIONS__... "  
 >&6; }
if test "${ac_cv_safe_to_define___extensions__+set}" = set; then
   $as_echo_n "(cached) " >&6
else
   cat >conftest.$ac_ext <<_ACEOF
/* confdefs.h.  */
_ACEOF
cat confdefs.h >>conftest.$ac_ext
cat >>conftest.$ac_ext <<_ACEOF
/* end confdefs.h.  */

#	  define __EXTENSIONS__ 1
	  $ac_includes_default
int
main ()
{

   ;
   return 0;
}
_ACEOF
rm -f conftest.$ac_objext
if { (ac_try="$ac_compile"
case "(($ac_try" in
   *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
   *) ac_try_echo=$ac_try;;
esac
eval ac_try_echo="\"\$as_me:$LINENO: $ac_try_echo\""
$as_echo "$ac_try_echo") >&5
   (eval "$ac_compile") 2>conftest.er1
   ac_status=$?
   grep -v '^ *+' conftest.er1 >conftest.err
   rm -f conftest.er1
   cat conftest.err >&5
   $as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
   (exit $ac_status); } && {
	 test -z "$ac_c_werror_flag" ||
	 test ! -s conftest.err
        } && test -s conftest.$ac_objext; then
   ac_cv_safe_to_define___extensions__=yes
else
   $as_echo "$as_me: failed program was:" >&5
sed 's/^/| /' conftest.$ac_ext >&5

	ac_cv_safe_to_define___extensions__=no
fi

rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
fi
{ $as_echo "$as_me:$LINENO: result:  
$ac_cv_safe_to_define___extensions__" >&5
$as_echo "$ac_cv_safe_to_define___extensions__" >&6; }
   test $ac_cv_safe_to_define___extensions__ = yes &&
     cat >>confdefs.h <<\_ACEOF
#define __EXTENSIONS__ 1
_ACEOF

   cat >>confdefs.h <<\_ACEOF
#define _ALL_SOURCE 1
_ACEOF

   cat >>confdefs.h <<\_ACEOF
#define _GNU_SOURCE 1
_ACEOF

   cat >>confdefs.h <<\_ACEOF
#define _POSIX_PTHREAD_SEMANTICS 1
_ACEOF

   cat >>confdefs.h <<\_ACEOF
#define _TANDEM_SOURCE 1
_ACEOF

I think this new section is the source of some extra lines in config.h:

/* Enable general extensions on Solaris.  */
#ifndef __EXTENSIONS__
# define __EXTENSIONS__ 1
#endif

The definition of __EXTENSIONS__ as 1 instead of blank conflicts with  
the #define __EXTENSIONS__ in src/backend/file/sixtp-dom-generators.c

If I'm running with --enable-error-on-warning, the build stops because  
__EXTENSIONS__ is being redefined in sixtp-dom-generators.

Shouldn't there be a test or an undef before the #defines in
lib/libqof/qof/gnc-date.c
macros/legacy_macros.m4
src/backend/file/sixtp-dom-generators.c
src/backend/file/sixtp-utils.c
?

The actual error I get is:

  gcc -DHAVE_CONFIG_H -I. -I../../.. -DG_LOG_DOMAIN=\"gnc.backend.xml 
\" -I/sw/include -I.. -I../.. -DLOCALE_DIR=\"/opt/gnucash-gda/share/ 
locale\" -I../../../src/backend -I../../../src/engine -I../../../src/ 
core-utils -I../../../lib/libc -I/sw/include/libxml2 -I../../../lib/ 
libqof/qof -I../../../lib/libqof/qof -I/sw/include/glib-2.0 -I/sw/lib/ 
glib-2.0/include -I/sw/include/glib-2.0 -I/sw/lib/glib-2.0/include -I/ 
sw/include/orbit-2.0 -I/sw/include/gconf/2 -DORBIT2=1 -Werror - 
Wdeclaration-after-statement -Wno-pointer-sign -D_FORTIFY_SOURCE=2 -g - 
Wno-unused -MT sixtp-dom-generators.lo -MD -MP -MF .deps/sixtp-dom- 
generators.Tpo -c sixtp-dom-generators.c  -fno-common -DPIC -o .libs/ 
sixtp-dom-generators.o
sixtp-dom-generators.c:26:1: error: "__EXTENSIONS__" redefined
In file included from sixtp-dom-generators.c:24:
../../../config.h:337:1: error: this is the location of the previous  
definition
make[5]: *** [sixtp-dom-generators.lo] Error 1

Mac OS X 10.5.3, ppc machine
gcc 4.0.1, autoconfig 2.62, m4 1.4.11, automake 1.9.6 or 1.10.1

Dave
--
David Reiser
dbreiser at earthlink.net