configure.ac: Always define __STDC_LIMIT_MACROS.
configure.ac: Always define __STDC_LIMIT_MACROS.

... which ensures that we get defines like LONG_MAX in C++.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=91591
Reviewed-by: Jose Fonseca <61b5a29db2c0650f7c8510f93eece059c1b09320@vmware.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler