gh-103053: Fix BUILDPYTHON target of Makefile

The BUILDPYTHON target of Makefile now uses "-o $(BUILDPYTHON)"
instead of "-o $@". On FreeBSD when Python is built out of tree,
"$@" contains the source directory, whereas the build directory is
expected.

Author: vstinner

Makefile.pre.in

@@ -783,7 +783,10 @@ clinic-tests: check-clean-src $(srcdir)/Lib/test/clinic.test.c
 
 # Build the interpreter
 $(BUILDPYTHON):	Programs/python.o $(LINK_PYTHON_DEPS)
-	$(LINKCC) $(PY_CORE_LDFLAGS) $(LINKFORSHARED) -o $@ Programs/python.o $(LINK_PYTHON_OBJS) $(LIBS) $(MODLIBS) $(SYSLIBS)
+	@ # gh-103053: Use "-o $(BUILDPYTHON)" instead of "-o $@".
+	@ # On FreeBSD when Python is built out of tree, $@ contains the source
+	@ # directory, whereas the build directory is expected.
+	$(LINKCC) $(PY_CORE_LDFLAGS) $(LINKFORSHARED) -o $(BUILDPYTHON) Programs/python.o $(LINK_PYTHON_OBJS) $(LIBS) $(MODLIBS) $(SYSLIBS)
 
 platform: $(PYTHON_FOR_BUILD_DEPS) pybuilddir.txt
 	$(RUNSHARED) $(PYTHON_FOR_BUILD) -c 'import sys ; from sysconfig import get_platform ; print("%s-%d.%d" % (get_platform(), *sys.version_info[:2]))' >platform