We do not write through our use of mmap(), so make sure callers pass
MAP_PRIVATE and remove support for writing changes back.
Signed-off-by: Junio C Hamano <junkio@cox.net>
Since some platforms do not support mmap() at all, and others do only just
so, this patch introduces the option to fake mmap() and munmap() by
malloc()ing and read()ing explicitely.
Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>