Patch to EF_MIPS_ARCH and EF_MIPS_MACH handling

[Thiemo Seufer]

Richard Sandiford wrote:
> This patch is basically the same as:
> 
>     http://sources.redhat.com/ml/binutils/2002-12/msg00078.html
> 
> but with one of the error messages changed slightly to be more
> consistent with the rest.  The patch includes a test case for
> various good and bad combinations.
> 
> To recap, the idea is to merge bfds based on their bfd_mach
> and update the check for 32-bit/64-bit collisions.  The patch
> allows o32 code for 64-bit targets to be linked with o32
> code for 32-bit targets.  Start of original thread:
> 
>     http://sources.redhat.com/ml/binutils/2002-11/msg00073.html
> 
> Tested on mips64-elf, mips-elf and mipsel-linux-gnu, no regressions.
> OK to install?

FWIW, I like it.


Thiemo