diff --git a/GNUmakefile.in b/GNUmakefile.in
index d027874c5be93dbf66052e7b0963a7947ad8a615..747253ec0ed54bcd43fb37c731ea402dbf576e06 100644
--- a/GNUmakefile.in
+++ b/GNUmakefile.in
@@ -40,7 +40,7 @@ ifeq ($(ISMAINSITE),1)
 SUBDIRS += tools/rmanage
 endif
 ifeq ($(PGENISUPPORT),1)
-SUBDIRS = protogeni
+SUBDIRS += protogeni
 endif
 else
 SUBDIRS = db tbsetup account protogeni