diff --git a/Doc/Makefile b/Doc/Makefile
index 2a8765b3970..538fb741436 100644
--- a/Doc/Makefile
+++ b/Doc/Makefile
@@ -126,6 +126,7 @@ tut-all:  tut.dvi tut.pdf tut.ps l2htut
 # This rule avoids creation of the intermediate PostScript files and uses
 # only free software.
 #
+$(PDFFILES): tools/toc2bkm.py
 .dvi.pdf: $*.bkm
 	$(PDFLATEX) $*
 	$(PYTHON) tools/toc2bkm.py $*