Borrow from NO_MMAP patch by Johannes, squelch compiler warnings by
declaring gitstrcasestr() when we use it.
Signed-off-by: Junio C Hamano <junkio@cox.net>
Also make platform specific part more isolated. Currently we only
have Darwin defined, but I've taken a look at SunOS specific patch
(which I dropped on the floor for now) as well. Doing things this way
would make adding it easier.
Signed-off-by: Junio C Hamano <junkio@cox.net>