Hi,

This patch makes the remote mips targets (mips,pmon,ddb,lsi) register a
thread in GDB's thread list.

While going through the file, I noticed a couple of other issues:

- nowhere in the file was inferior_ptid set, but there
  were places where it was being set to null_ptid (you can
  see one such place in the patch).

- mips_load was clearing inferior_ptid, and calling clear_symtab_users.  I 
  notice that inferior_ptid is being cleared after a load command, but that
  is wrong, I believe.  See this change of Jim's to monitor.c, that removed
  this clearing from the monitor target:
   http://sourceware.org/ml/gdb/2001-09/msg00125.html

  I'm applying the exact same reasoning and change here.

- There's a FIXME in mips_create_inferior, wondering if it should set
  inferior_ptid there.  I believe the answer is negative.  When you get to
  mips_create_inferior, the target is already with execution -- you have it
  since target_open.  The "run" command against this target merelly sets
  the PC to the entry points, and proceeds.  The user could have also
  just "target mips ..." followed by "continue".  See Jim's email above, his
  very nice explanation makes it clearer.

This hasn't been tested at all, but, does it looks reasonable?

-- 
Pedro Alves