finish implementing pmatchregex

finish implementing pmatchregex

I started out cleaning up a bit of lint in the recent run-time options
handling and discovered that pmatchregex wasn't finished.  Finish it and
also deal with the version lint.  Argument declarations for function
definitions in pmatchregex.c have been switched to K&R style.  (The ones
in posixregex.c have been left in ANSI style.)

There wasn't any build rule for pmatchregex.o; now there is (for Unix).
posixregex.o is still the default.

There isn't any build rule for cppregex.o (again, for Unix); the change
to cppregex.cpp is untested.