[PATCH:app/xinit] Use platform-specific X server names in man pages for cygwin & darwin

[Alan Coopersmith]

I meant to note that I've only tested on Solaris, not cygwin or darwin,
so am relying on those platform maintainers to let me know if it doesn't
work there or if those aren't the best values to use (I went with what
I saw in the xserver hw/* man pages).

-- 
	-Alan Coopersmith-           alan.coopersmith at sun.com
	 Sun Microsystems, Inc. - X Window System Engineering