help with windows tinbuild and symlinks

[Tor Lillqvist]

> Is it a speed issue?

If it is, one solution would be to require our own make fork on Cygwin
(it is very much recommended already), and add some suitable $(cygpath
...) function to it (probably two: cygpath_to_windows and
winpath_to_cygwin, or something), which would call the appropriate
Cygwin library function instead of executing a cygpath.exe subprocess.

--tml