Fix building with setuptools instead of distutils.

--- libseccomp-2.5.4.orig/src/python/Makefile.am
+++ libseccomp-2.5.4/src/python/Makefile.am
@@ -40,7 +40,8 @@ build: ../libseccomp.la libseccomp.pxd s
 
 install-exec-local: build
 	${PY_INSTALL} --install-lib=${DESTDIR}/${pyexecdir} \
-		--record=${DESTDIR}/${pyexecdir}/install_files.txt
+		--record=${DESTDIR}/${pyexecdir}/install_files.txt \
+		--single-version-externally-managed
 
 uninstall-local:
 	cat ${DESTDIR}/${pyexecdir}/install_files.txt | xargs ${RM} -f