papi: fix building on aarch64

Change-Id: I3983576bd4e0f197193a7d281763d545a55e7d64
Signed-off-by: Damjan Marion <damarion@cisco.com>
diff --git a/src/vpp-api/python/Makefile.am b/src/vpp-api/python/Makefile.am
index b8ca153..a5dabc3 100644
--- a/src/vpp-api/python/Makefile.am
+++ b/src/vpp-api/python/Makefile.am
@@ -42,7 +42,7 @@
 	cd $(srcdir);							\
 	mkdir -p $(prefix)/lib/python2.7/site-packages; 		\
 	PYTHONUSERBASE=$(prefix)					\
-	python setup.py build_ext -L $(prefix)/lib64 \
+	python setup.py build_ext -L $(libdir)				\
 	-I $(prefix)/include/ install --user
 
 #