crosstest: Fix the crosstest dependencies.
diff --git a/dlls/Maketest.rules.in b/dlls/Maketest.rules.in
index b112c45..aff002c 100644
--- a/dlls/Maketest.rules.in
+++ b/dlls/Maketest.rules.in
@@ -24,6 +24,7 @@
 CROSSTEST    = $(TESTDLL:%.dll=%)_crosstest.exe
 CROSSCC      = @CROSSCC@
 CROSSWINEGCC = $(TOOLSDIR)/tools/winegcc/winegcc @CROSSTARGETFLAGS@ -B$(TOOLSDIR)/tools/winebuild --sysroot=$(TOPOBJDIR)
+MAKEDEPFLAGS = -xo -xcross.o
 
 @MAKE_RULES@