Move -D, -U and -A into the front end

[Neil Booth]

Andreas Jaeger wrote:-

> /cvs/gcc/gcc/treelang/treetree.c:997: warning: no previous prototype for `cpp_handle_option'
> make[2]: *** [treelang/treetree.o] Error 1
> 
> Since you removed this function, I removed it in treelang also and
> committed the appended patch as obvious.

Great, thanks.  I will do my best to remember to add treelang when
changing interfaces in the future.

Neil.