building xemacs-pacakges on unix

I tried building the packages from source. Even doing a make clean in the root of the xemacs packages source tree takes ages. This is because the XEmacs.rules file contains: ----- XEMACS_NATIVE_NT = \ $(shell $(XEMACS) $(VANILLA) -batch \ -eval "(princ (eq system-type 'windows-nt))") ----- this is executed for every single directory in the whole source tree (i.e. for all 110 Makefiles). I am all in favour of compatability with different OSs, but could this please be done slightly more efficiently? e.g. only do this once instead of 110 time? Gunnar