Bug 1373525 - gfx/angle: Suppress -Wimplicit-fallthrough warnings in third-party code. r=jgilbert

gfx/angle/src/compiler/translator/ASTMetadataHLSL.cpp:93:15 [-Wimplicit-fallthrough] unannotated fall-through between switch labels
gfx/angle/src/compiler/translator/ParseContext.cpp:1123:9 [-Wimplicit-fallthrough] unannotated fall-through between switch labels
gfx/angle/src/compiler/translator/ParseContext.cpp:3640:9 [-Wimplicit-fallthrough] unannotated fall-through between switch labels
gfx/angle/src/compiler/translator/ParseContext.cpp:3808:9 [-Wimplicit-fallthrough] unannotated fall-through between switch labels
gfx/angle/src/compiler/translator/util.cpp:216:15 [-Wimplicit-fallthrough] unannotated fall-through between switch labels
gfx/angle/src/compiler/translator/util.cpp:225:15 [-Wimplicit-fallthrough] unannotated fall-through between switch labels
gfx/angle/src/compiler/translator/util.cpp:234:15 [-Wimplicit-fallthrough] unannotated fall-through between switch labels

MozReview-Commit-ID: EExTKYUzXB

--HG--
extra : source : cb3ff4fc33a9282d5153933e86d943cb53d360dd
extra : intermediate-source : 075e2107d6003a909029881ddfbfa1ef00610eb7
extra : histedit_source : d56ed92f0f244b1e0130d02ab7d665b4f096ae10

gfx/angle/moz.build

@@ -128,6 +128,7 @@ if CONFIG['GNU_CXX']:
     ]
     if CONFIG['CLANG_CXX']:
         CXXFLAGS += [
+            '-Wno-implicit-fallthrough',
             '-Wno-inconsistent-missing-override',
             '-Wno-unused-private-field',
         ]