Revert "Android: Enable C99 mode instead of C89 (default)."

webrtc/BUILD.gn

Index: webrtc/BUILD.gn
diff --git a/webrtc/BUILD.gn b/webrtc/BUILD.gn
index 56d06cf1291d66684004a03dc4441a967f9b014a..40368597b22dc5cab2ef3215c8d6bd8159defd64 100644
--- a/webrtc/BUILD.gn
+++ b/webrtc/BUILD.gn
@@ -154,18 +154,14 @@ config("common_config") {
   }
 
   if (is_android && !is_clang) {
+    # The Android NDK doesn"t provide optimized versions of these
+    # functions. Ensure they are disabled for all compilers.
     cflags += [
-      # The Android NDK doesn't provide optimized versions of these
-      # functions. Ensure they are disabled for all compilers.
       "-fno-builtin-cos",
       "-fno-builtin-sin",
       "-fno-builtin-cosf",
       "-fno-builtin-sinf",
     ]
-    cflags_c = [
-      # Use C99 mode instead of C89 (default).
-      "-std=c99",
-    ]
   }
 }