scons: Always define __STDC_LIMIT_MACROS.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=91591
Signed-off-by: Vinson Lee <vlee@freedesktop.org>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>

scons/gallium.py

@@ -300,6 +300,7 @@ def generate(env):
 
     # C preprocessor options
     cppdefines = []
+    cppdefines += ['__STDC_LIMIT_MACROS']
     if env['build'] in ('debug', 'checked'):
         cppdefines += ['DEBUG']
     else: