tools/python: pass more -rpath-link options to ld

With the split of libraries, I've observed a number of warnings from
(old?) ld.

Instead of duplicating the additions in two places, introduce a setup.py
make variable holding all the common parts of the invocations.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>

tools/python/Makefile

@@ -8,19 +8,21 @@ PY_CFLAGS = $(CFLAGS) $(PY_NOOPT_CFLAGS)
 PY_LDFLAGS = $(SHLIB_LDFLAGS) $(APPEND_LDFLAGS)
 INSTALL_LOG = build/installed_files.txt
 
+setup.py = CC="$(CC)" CFLAGS="$(PY_CFLAGS)" LDSHARED="$(CC)" LDFLAGS="$(PY_LDFLAGS)" \
+           SHLIB_libxenctrl="$(SHLIB_libxenctrl)" \
+           SHLIB_libxenguest="$(SHLIB_libxenguest)" \
+           SHLIB_libxenstore="$(SHLIB_libxenstore)" \
+           $(PYTHON) setup.py
+
 .PHONY: build
 build:
-	CC="$(CC)" CFLAGS="$(PY_CFLAGS)" LDSHARED="$(CC)" LDFLAGS="$(PY_LDFLAGS)" $(PYTHON) setup.py build
+	$(setup.py) build
 
 .PHONY: install
 install:
 	$(INSTALL_DIR) $(DESTDIR)$(LIBEXEC_BIN)
-
-	CC="$(CC)" CFLAGS="$(PY_CFLAGS)" LDSHARED="$(CC)" \
-		LDFLAGS="$(PY_LDFLAGS)" $(PYTHON) setup.py install \
-		--record $(INSTALL_LOG) $(PYTHON_PREFIX_ARG) \
+	$(setup.py) install --record $(INSTALL_LOG) $(PYTHON_PREFIX_ARG) \
 		--root="$(DESTDIR)" --force
-
 	$(INSTALL_PYTHON_PROG) scripts/convert-legacy-stream $(DESTDIR)$(LIBEXEC_BIN)
 	$(INSTALL_PYTHON_PROG) scripts/verify-stream-v2 $(DESTDIR)$(LIBEXEC_BIN)