cygport no longer removes "cygwin" from the dependency list

[Ken Brown]

Now that we've moved from cygwin-1.7.x to cygwin-2.x.y, line 681 of 
pkg_pkg.cygpart no longer filters out "cygwin".  Presumably you just 
want to replace "cygwin-1" by "cygwin-2", unless there's a reason to 
allow for the possibility that maintainers are building without having 
the latest version of cygwin installed.

Ken