Makefile: work better with parallel make
Add some dependency information to the Makefile so that it doesn't fail if make is run with -j # (e.g. because MAKEFLAGS includes -j #).
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Add some dependency information to the Makefile so that it doesn't fail if make is run with -j # (e.g. because MAKEFLAGS includes -j #).