A gcc/f Makefile patch

[H.J. Lu]

> 
> HJ, thanks for this patch, it looks entirely safe.  Could you let me know
> whether you think the same thing should be done for the g77$(exeext)
> and g77-cross$(exeext) targets, which I was also (somewhat intentionally,
> not knowing the implications vis-a-vis parallel make) somewhat lazy
> about?  If so, you're welcome to submit a patch if only to save me
> the bother.

g77$(exeext) and g77-cross$(exeext) are fine since they depend on
those who will touch lang-f77.


H.J.