Use -fno-common for mingw

Fixes http://code.google.com/p/webm/issues/detail?id=112

Thanks to Ramiro Polla for the issue/fix.

Change-Id: I7f7b547a4ea3270e183f59280510066cc29a619e

build/make/configure.sh

@@ -781,6 +781,9 @@ process_common_toolchain() {
         soft_enable ssse3
 
         case  ${tgt_os} in
+            win*)
+                enabled gcc && add_cflags -fno-common
+                ;;
             solaris*)
                 CC=${CC:-${CROSS}gcc}
                 LD=${LD:-${CROSS}gcc}