Solaris 9 doesn't have mkdtemp() so we need to emulate it for the
rsync transport implementation. Since Solaris 9 is lacking this
function we can also reasonably assume it is not available on
Solaris 8 either. The new Makfile definition NO_MKDTEMP can be
set to enable the git compat version.
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>