Support !test? conditionals in RESTRICT (bug 663278)

Since RESTRICT="!test? ( test )" can be very useful within the context
of bug 663278, pass an appropriate uselist parameter to the RESTRICT
use_reduce call. Make self.configdict["features"]["USE"] independent
of IUSE and RESTRICT, so that the same value can be shared between
packages with different settings, which is important when evaluating
USE conditional RESTRICT. When the evaluated value of RESTRICT contains
"test", handle it like IUSE="-test", since features USE is independent
of RESTRICT.

Bug: https://bugs.gentoo.org/663278
1 file changed