reimplement find_machine()
reimplement find_machine()

find_machine() can be inlined and not acessible to be evaluated,
so we have to reimplement it ourselves.

Signed-off-by: Eduardo Habkost <50373d7c08ceadf576dd7dca718012445b677ce6@redhat.com>

ehabkost/gdb-qemu,ehabkost/gdb-qemu