* configure.in (AC_PREREQ): Bump to 2.13.
        (AC_C_STRINGIZE): Call this instead of using a custom macro.

        * gansidecl.h (HAVE_STRINGIZE): Define, if stage2 gcc && __STDC__.

        * system.h (HAVE_STRINGIZE): Test this instead of HAVE_CPP_STRINGIFY.

        * acconfig.h (HAVE_CPP_STRINGIFY): Delete.

        * alpha/xm-vms.h (HAVE_CPP_STRINGIFY): Delete.
        (HAVE_STRINGIZE): Define.

From-SVN: r29590