Would it be possible to add this dependency to $(BUILD_PYTHON) instead, to fix more "make" commands?

Yes, this is much better and would cover all cases I think.

BTW a '.PHONY' declaration is missing for check-clean-src.

I suggest to use Objects/object.o instead, since the compilation may have succeed to build object.o but failed to build python.o (or failed before trying to build python.o).

Actually Programs/python.o is the first object built by the Makefile as it is the first prerequisite in the $(BUILDPYTHON) rule.

Actually Programs/python.o is the first object built by the Makefile as it is the first prerequisite in the $(BUILDPYTHON) rule.

Oh ok, I see. I that case, it's fine :-)

I would prefer to put check-clean-src in $(BUILDPYTHON). I tested, it works:

# Build the interpreter
$(BUILDPYTHON):	check-clean-src Programs/python.o $(LIBRARY) $(LDLIBRARY) $(PY3LIBRARY)
	$(LINKCC) $(PY_LDFLAGS) $(LINKFORSHARED) -o $@ Programs/python.o $(BLDLIBRARY) $(LIBS) $(MODLIBS) $(SYSLIBS) $(LDLAST)

1. One problem is that in this case the $(BUILDPYTHON) target is rebuilt even when it is up to date, for the following reason:

A phony target should not be a prerequisite of a real target file;
if it is, its recipe will be run every time make goes to update that file.

This is a quote from Phony Targets.

2. Another minor problem is that the recipe of check-clean-src may be run multiple times.

Oh oh, I didn't know.

The error message is not easy to understand. I propose:

		echo "Error: The source directory ($(srcdir)) is not clean" ; \
		echo "Building Python out of the source tree ($(abs_builddir)) requires a clean source tree ($(abs_srcdir)" ; \
		echo "Try to run: make -C \"$(srcdir)\" clean" ; \

At least, the proposed command worked for me ;-)

Ok

Oh oh, I didn't know.