link.exe --help, -E/-o
link.exe --help, -E/-o

	* msvc/link.exe (usage): New.
	This simplifies the access to MSVC's options.
	(get_options): Don't try to guess the options to pass to specify
	the output file too soon, so that we can use -o with -E too.
	(mode): Make it more explicit that mode=link exists.

aldebaran/libport,aldebaran/libport,aldebaran/libport,aldebaran/libport,aldebaran/libport