Index: help/Makefile.in
--- help/Makefile.in.orig
+++ help/Makefile.in
@@ -648,7 +648,7 @@ C/figures/%.png:
 	-cp -f ../src/icons/$(notdir $@) C/figures/
 
 %.1: %.xml
-	$(XSLTPROC) -o $@ http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl $<
+	$(XSLTPROC) -o $@ $(prefix)/share/xsl/docbook/manpages/docbook.xsl $<
 
 # Tell versions [3.59,3.63) of GNU make to not export all variables.
 # Otherwise a system limit (for SysV at least) may be exceeded.
