This patch adds process recording support to moxie-elf-gdb.  This
enables reverse debugging on both the gdb simulator as well as the moxie
qemu port.

I've also added support for libgloss system calls, so gdb knows how to
undo the handful of I/O routines invoked by the "swi" instruction
(software interrupt).

Testsuite results are OK.  I believe the reverse debugging failures are
unrelated to recording or reverse debugging.

I'm checking this patch in.

Thanks,

AG