tools: Added 'relpath' tool to compute relative Unix paths.
diff --git a/Make.rules.in b/Make.rules.in
index ddc9274..9deee72 100644
--- a/Make.rules.in
+++ b/Make.rules.in
@@ -72,6 +72,7 @@
 WMC          = $(TOOLSDIR)/tools/wmc/wmc
 WIDL         = $(TOOLSDIR)/tools/widl/widl
 WINEGCC      = $(TOOLSDIR)/tools/winegcc/winegcc
+RELPATH      = $(TOOLSDIR)/tools/relpath
 SFNT2FNT     = $(TOOLSDIR)/tools/sfnt2fnt
 FNT2FON      = $(TOOLSDIR)/tools/fnt2fon
 RC           = $(WRC)