Change STRERROR() to be just an alias for strerror() on all platforms

Its a terrible idea to modify the return value of strerror() on any platform. strerror() can (and often does) return immutable string constants - don't try to modify that string even if it does end in trailing white-space (find another solution to that). This change only affects non-*nix builds since we were already doing the right thing for *nix.