bpo-21536: Revert Makefile change on python-config (GH-12971)

bpo-21536: Revert Makefile change on python-config (GH-12971) · python/cpython@01f073f

Original file line number	Diff line number	Diff line change
`@@ -1460,7 +1460,9 @@ libinstall: build_all $(srcdir)/Modules/xxmodule.c`
`1460`	`1460`	`-PYTHONPATH=$(DESTDIR)$(LIBDEST) $(RUNSHARED) \`
`1461`	`1461`	`$(PYTHON_FOR_BUILD) -m lib2to3.pgen2.driver $(DESTDIR)$(LIBDEST)/lib2to3/PatternGrammar.txt`
`1462`	`1462`
`1463`		`-python-config: $(srcdir)/Misc/python-config.in $(srcdir)/Misc/python-config.sh`
	`1463`	`+# bpo-21536: Misc/python-config.sh is generated in the build directory`
	`1464`	`+# from $(srcdir)Misc/python-config.sh.in.`
	`1465`	`+python-config: $(srcdir)/Misc/python-config.in Misc/python-config.sh`
`1464`	`1466`	`@ # Substitution happens here, as the completely-expanded BINDIR`
`1465`	`1467`	`@ # is not available in configure`
`1466`	`1468`	`sed -e "s,@EXENAME@,$(BINDIR)/python$(LDVERSION)$(EXE)," < $(srcdir)/Misc/python-config.in >python-config.py`