Mount NODEFS on /x if using emscripten and nodejs
Mount NODEFS on /x if using emscripten and nodejs

This is useful for testing

SymbiFlow/arachne-pnr,cseed/arachne-pnr,SymbiFlow/arachne-pnr,cseed/arachne-pnr,cseed/arachne-pnr,SymbiFlow/arachne-pnr