--- a/media/ffvpx/ffvpxcommon.mozbuild
+++ b/media/ffvpx/ffvpxcommon.mozbuild
@@ -29,35 +29,39 @@ if CONFIG['FFVPX_ASFLAGS']:
     else:
         # Default to unix, similar to how ASFLAGS setup works in configure.in
         ASFLAGS += ['-Pconfig_unix64.asm']
 
 LOCAL_INCLUDES += ['/media/ffvpx']
 
 # We allow warnings for third-party code that can be updated from upstream.
 ALLOW_COMPILER_WARNINGS = True
+
 # Suppress warnings in third-party code.
 if CONFIG['GNU_CC']:
     CFLAGS += [
         '-Wno-parentheses',
         '-Wno-pointer-sign',
         '-Wno-sign-compare',
         '-Wno-switch',
         '-Wno-type-limits',
         '-Wno-unused-function',
         # XXX This does not seem to have any effect on some versions of GCC.
         '-Wno-deprecated-declarations',
-        '-Wno-discarded-qualifiers',
-        '-Wno-maybe-uninitialized',
     ]
     if CONFIG['CLANG_CXX']:
         CFLAGS += [
             '-Wno-incompatible-pointer-types-discards-qualifiers',
             '-Wno-logical-op-parentheses',
         ]
+    else:
+        CFLAGS += [
+            '-Wno-discarded-qualifiers',
+            '-Wno-maybe-uninitialized',
+        ]
     # Force visibility of cpu and av_log symbols.
     CFLAGS += ['-include', 'libavutil_visibility.h']
 elif CONFIG['_MSC_VER']:
     CFLAGS += [
         '-wd4090', # 'return' : different 'const' qualifiers
         '-wd4018', # '>' : signed/unsigned mismatch
         '-wd4305', # 'initializing' : truncation from '__int64' to 'double'
         '-wd4554', # '>>' : check operator precedence for possible error