diff --git a/doc/GNUmakefile b/doc/GNUmakefile
index 452fa765dc..0629d0fdd5 100644
--- a/doc/GNUmakefile
+++ b/doc/GNUmakefile
@@ -9,6 +9,9 @@ MAKESUBDIRS = @for dir in $(SUBDIRS); do \
 all postscript:		
 	$(MAKESUBDIRS)
 
+pdf:
+	$(MAKESUBDIRS)
+
 html:
 	$(MAKESUBDIRS)