Index: python/louis/Makefile.in
--- python/louis/Makefile.in.orig
+++ python/louis/Makefile.in
@@ -1587,7 +1587,7 @@ uninstall-am:
 
 
 all:
-	source ../../liblouis/liblouis.la ; \
+	. ../../liblouis/liblouis.la ; \
 	sed "s/###LIBLOUIS_SONAME###/$$dlname/" \
 		< $(srcdir)/__init__.py.in \
 		> __init__.py
