gnu make tutorial

[M.W. Chang]

>> rlib.o : rlib.prg
>> # %.o : %.prg
>> .prg.o :
>>         gharbour $<
> I believe that's exactly what happened. The implicit rules are used
> first. I think you must use an explicit rule in this case because you
> are not using a compiler that GCC has been taught to use and you are
> using a non-standard file extension.

So there is no way to specify a non-standard rule in the ".prg.o" way?
I could use "%.o : %.prg", but I am curious about the possibility.