[parisc-linux] new method for 64-bit parisc tree

[bame@riverrock.org]

I want to hear concerns because without serious ones I'm going to
make this change next week...

= Instead, can't you simply play tricks with -I, and add a symbolic link
= asm -> ../asm-parisc in asm-parisc64)?  The idea being to end up with
= an include path looking like
= "-I $(TOPDIR)/include -I $(TOPDIR)/include/asm"
= 
= That way, asm/foo.h is found by the first -I if we have asm-parisc64/foo.h,
= and is found by the second if asm-parisc/foo.h exists but not
= asm-parisc64/foo.h.  Hmm, you might also need -I-

That would function fine for header files, but not for source files
where something like VPATH might work, but is not available to us.  It's
worth noting that both -I and VPATH tricks mean if you have an error
in or need to change a file, you may have to examine two
directories to figure out where it really lives.  The symbolic link
scheme solves some of that problem.

	-P