enable n32 and n64, and move o32 into mips/mips32

[Roland McGrath]

> Anyway, this patch fixes all of the linuxthreads build problems I've
> run into.  Ok?
> 
> Index: linuxthreads/ChangeLog
> from  Alexandre Oliva  <aoliva@redhat.com>
> 
> 	* alloca_cutoff.c: Include internals.h.
> 	* sysdeps/pthread/errno-loc.c: Include linuxthreads/internals.h.
> 	* sysdeps/pthread/herrno-loc.c: Likewise.
> 	* sysdeps/pthread/res-state.c: Likewise.

Those are fine.