Don't pass the -nostdinc++ parameter to clang from emcc, since it spams the line "clang++: warning: argument unused during compilation: '-nostdinc++'" for each built .cpp file.

tools/shared.py

@@ -197,7 +197,7 @@ USE_EMSDK = not os.environ.get('EMMAKEN_NO_SDK')
 if USE_EMSDK:
   # Disable system C and C++ include directories, and add our own (using -idirafter so they are last, like system dirs, which
   # allows projects to override them)
-  EMSDK_OPTS = ['-nostdinc', '-nostdinc++', '-Xclang', '-nobuiltininc', '-Xclang', '-nostdinc++', '-Xclang', '-nostdsysteminc',
+  EMSDK_OPTS = ['-nostdinc', '-Xclang', '-nobuiltininc', '-Xclang', '-nostdinc++', '-Xclang', '-nostdsysteminc',
     '-Xclang', '-isystem' + path_from_root('system', 'include'),
     '-Xclang', '-isystem' + path_from_root('system', 'include', 'emscripten'),
     '-Xclang', '-isystem' + path_from_root('system', 'include', 'bsd'), # posix stuff