runtime(tutor): update Makefile and make it portable between GNU and BSD Commit: https://github.com/vim/vim/commit/1869fe0ce6f0c1cc37e02623b2a372e1c81f6864 Author: RestorerZ <restorer@mail2k.ru> Date: Thu Aug 15 21:51:32 2024 +0200 runtime(tutor): update Makefile and make it portable between GNU and BSD by removing the non-portable GNU variable and using $? instead Note: this only works for rules with single dependencies. closes: #15502 related: #15493 Signed-off-by: RestorerZ <restorer@mail2k.ru> Signed-off-by: Christian Brabandt <cb@256bit.org>