Okay so my “make -t” trick has various flaws. You still have to know the filenames to specify, it requires Makefile to be generated by configure in the source tree, and it creates empty files if you use it in a separate build directory.

Another idea: instead of the “make touch” recipe, we add a simple shell script. Call it say “touch-bootstrap.sh”. Like what “make touch” already does in Python 2, but without embedding it as a makefile rule.

Or add a flag variable so you can do a build without running any of the regeneration rules or worrying about timestamps: make BOOT="#".