compiler/natives/src/syscall: Rename syscall
compiler/natives/src/syscall: Rename syscall

On Darwin, syscall was instroduced at https://github.com/golang/go/commit/a3b01440fef3d2833909f6651455924a1c86d192.

This change renames syscall to avoid collision.

gopherjs/gopherjs,gopherjs/gopherjs,gopherjs/gopherjs,gopherjs/gopherjs,gopherjs/gopherjs