[Patch]: Support VMS in libstdc++ crossconfig.m4

[Tristan Gingold]

Hi,

currently all VMS compilers are built on Unix.  So, to build the libstdc++ 
library, this looks like the minimum required.

Tested by build libstdc++ for ia64-hp-openvms.

Ok for trunk ?

Tristan.

libstdc++/
2012-03-30  Tristan Gingold  <ging...@adacore.com>

        * crossconfig.m4 (*-*-*vms*): Add.
        * configure: Regenerate.

diff --git a/libstdc++-v3/crossconfig.m4 b/libstdc++-v3/crossconfig.m4
index 3850879..e208fbf 100644
--- a/libstdc++-v3/crossconfig.m4
+++ b/libstdc++-v3/crossconfig.m4
@@ -241,6 +241,12 @@ case "${host}" in
       AC_DEFINE(HAVE_ISNANL)
     fi
     ;;
+  *-*vms*)
+    # Check for available headers.
+    # Don't call GLIBCXX_CHECK_LINKER_FEATURES, VMS doesn't have a GNU ld
+    GLIBCXX_CHECK_MATH_SUPPORT
+    GLIBCXX_CHECK_STDLIB_SUPPORT
+    ;;
   *-vxworks)
     AC_DEFINE(HAVE_ACOSF)
     AC_DEFINE(HAVE_ASINF)