There's a random string "some-random-string-to-id-this-makefile" in
projects-dir-minimial.mk intended to check if the Makefile in the
projects-directory is actually the final link target. It's re-used in
pgit.sh to find the projects toplevel directory, but since it doesn't need
to be an actual projects-dir-minimal.mk copy, another case should also be
taken into consideration: Check if projects-dir.mk is included.
Signed-off-by: Jan Lindemann <jan@janware.com>