git-gui: sync Makefiles with git.git
In git.git, commit 5309c1e9fb39 (Makefile: set default goals in
makefiles, 2025-02-15) touched two Makefiles in the git-git/ directory.
Import these changes, so that the trees can converge again with the
next merge of this repository into git.git.
Reported-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Johannes Sixt <j6t@kdbg.org>
authored by