That way we avoid any confusion with "GNU Interactive Tools", and it's
more descriptive anyway (the rpm documentation talks about how git is
split into a "core" part and an "SCM" part, this makes it clear that
this is the core one).
targets: git.spec, dist, and rpm. A simple 'make rpm' will build the rpm.
Also adds git.spec.in which is used to generate git.spec.
Signed-off-by: Chris Wright <chrisw@osdl.org>