winegcc: Don't pass the as/ld/nm commands to winebuild.

winebuild should be able to find them on its own.
diff --git a/Make.rules.in b/Make.rules.in
index 7066c98..3645603 100644
--- a/Make.rules.in
+++ b/Make.rules.in
@@ -62,7 +62,7 @@
 ALLLINTFLAGS = $(INCLUDES) $(DEFS) $(LINTFLAGS)
 IDLFLAGS     = $(INCLUDES) $(DEFS) $(EXTRAIDLFLAGS)
 TARGETFLAGS  = @TARGETFLAGS@
-WINEBUILDFLAGS = $(TARGETFLAGS) $(DLLFLAGS) --as-cmd "$(AS)"
+WINEBUILDFLAGS = $(TARGETFLAGS) $(DLLFLAGS)
 MKINSTALLDIRS= $(TOPSRCDIR)/tools/mkinstalldirs -m 755
 WINAPI_CHECK = $(TOPSRCDIR)/tools/winapi/winapi_check
 WINEWRAPPER  = $(TOPSRCDIR)/tools/winewrapper