Fix warning muting not ocurring at all levels

SConstruct

@@ -835,7 +835,7 @@ else:  # GCC, Clang
         if cc_version_major >= 12:  # False positives in our error macros, see GH-58747.
             common_warnings += ["-Wno-return-type"]
     elif methods.using_clang(env) or methods.using_emcc(env):
-        common_warnings += ["-Wshadow-field-in-constructor", "-Wshadow-uncaptured-local"]
+        common_warnings += ["-Wshadow-field-in-constructor", "-Wshadow-uncaptured-local", "-Wno-undefined-var-template"]
         # We often implement `operator<` for structs of pointers as a requirement
         # for putting them in `Set` or `Map`. We don't mind about unreliable ordering.
         common_warnings += ["-Wno-ordered-compare-function-pointers"]