[PATCH 2/3] gdb, amd64: remove unused forward declerations

[Tom Tromey]

>>>>> "Felix" == Felix Willgerodt <felix.willgerodt@intel.com> writes:

Felix> These structs are not referenced anywhere anymore and seemed to have been
Felix> missed at some point when their usage was removed.

Felix> Co-authored-by: Nils-Christian Kempke <nils-christian.kempke@intel.com>

Seems obvious to me.  Thanks.
Approved-By: Tom Tromey <tom@tromey.com>

Tom