scons: Build mesa source with c99.
diff --git a/src/mesa/SConscript b/src/mesa/SConscript
index db18c61..a77c3de 100644
--- a/src/mesa/SConscript
+++ b/src/mesa/SConscript
@@ -12,6 +12,11 @@
 	'#/src/mesa/main',
 ])
 
+env.Append(CFLAGS = [
+	'-std=c99',
+])
+
+
 #######################################################################
 # Core sources