gdb: add gdbarch_up

Add a gdbarch_up unique pointer type, that calls gdbarch_free on
deletion.  This is used in the ROCm support patch at the end of this
series.

Change-Id: I4b808892d35d69a590ce83180f41afd91705b2c8
Approved-By: Andrew Burgess <aburgess@redhat.com>
1 file changed