memory regions are "potentially overlapping" to a test that determines
that the regions are actually overlapping. Because the code for the
overlapping case is seven instructions longer, this signifcantly
improves performance in the average case.
th LIBC_RCS, the entire source tree should be updated at once.
Remove && !defined(lint) from conditionals around rcs id's. No one is
ever going to pass a *.s file through lint.