diff --git a/Make.rules.in b/Make.rules.in
index db84e90..a259da9 100644
--- a/Make.rules.in
+++ b/Make.rules.in
@@ -71,7 +71,7 @@
 WRC          = $(TOOLSDIR)/tools/wrc/wrc
 WMC          = $(TOOLSDIR)/tools/wmc/wmc
 WIDL         = $(TOOLSDIR)/tools/widl/widl
-WINEGCC      = $(TOOLSDIR)/tools/winegcc/winegcc $(TARGETFLAGS) -B$(TOOLSDIR)/tools/winebuild
+WINEGCC      = $(TOOLSDIR)/tools/winegcc/winegcc $(TARGETFLAGS) -B$(TOOLSDIR)/tools/winebuild --sysroot=$(TOPOBJDIR)
 RELPATH      = $(TOOLSDIR)/tools/relpath
 SFNT2FNT     = $(TOOLSDIR)/tools/sfnt2fnt
 FNT2FON      = $(TOOLSDIR)/tools/fnt2fon