gdbsupport: move libxxhash configure check to gdbsupport The following patch moves the fast_hash function, which uses libxxhash, to gdbsupport. Move the libxxhash configure check to gdbsupport (and transitively to gdbserver). Change-Id: I242499e50c8cd6fe9f51e6e92dc53a1b3daaa96e Approved-By: Andrew Burgess <aburgess@redhat.com>