bpo-21536: Revert Makefile change on python-config by vstinner · Pull Request #12971 · python/cpython

@vstinner

@vstinner

Misc/python-config.sh lives in the build directory, not in the source
directory.

@vstinner

When I build Python of the source tree, I can reproduce the bug without my change:

make: *** No rule to make target '/path_to_build_dir/Misc/python-config.sh', needed by 'python-config'.  Stop

I confirm with manual test that my change fix this use case.