browser-asmjs: Bump Emscripten to 1.37.21
browser-asmjs: Bump Emscripten to 1.37.21

thewtex/cross-compilers,dockcross/dockcross,dockcross/dockcross,thewtex/cross-compilers,thewtex/cross-compilers,dockcross/dockcross,thewtex/cross-compilers,dockcross/dockcross