--- WindowMaker/Defaults/Makefile.in.orig	2020-08-13 06:26:57 UTC
+++ WindowMaker/Defaults/Makefile.in
@@ -562,6 +562,7 @@ WMWindowAttributes: $(srcdir)/WMWindowAttributes.in
 
 WindowMaker: $(srcdir)/WindowMaker.in
 	$(AM_V_GEN)sed -e "s:#pkgdatadir#:$(pkgdatadir):" \
+		-e "s:#prefix#:$(prefix):" \
 		-e "s:#pixmapdir#:$(pixmapdir):" $(srcdir)/WindowMaker.in \
 		> WindowMaker ; \
 	chmod 644 WindowMaker
