Bug 1203476 - Fix an Android-only warning in mozalloc_abort.cpp. r=glandium.

And remove the corresponding and now-unnecessary ALLOW_COMPILER_WARNINGS=True.

memory/mozalloc/moz.build

@@ -40,9 +40,6 @@ GENERATED_INCLUDES += ['/xpcom']
 
 DISABLE_STL_WRAPPING = True
 
-if not CONFIG['CLANG_CXX'] and not CONFIG['_MSC_VER']:
-    ALLOW_COMPILER_WARNINGS = True
-
 DEFINES['IMPL_MFBT'] = True
 
 if CONFIG['_MSC_VER']:

memory/mozalloc/mozalloc_abort.cpp

@@ -78,6 +78,12 @@ void abort(void)
 #endif
 
     mozalloc_abort(msg);
+
+    // We won't reach here because mozalloc_abort() is MOZ_NORETURN. But that
+    // annotation isn't used on ARM (see mozalloc_abort.h for why) so we add a
+    // redundant MOZ_CRASH() here to avoid a "'noreturn' function does return"
+    // warning.
+    MOZ_CRASH();
 }
 #endif