Add gdb_rl_tilde_expand, a wrapper around readline's tilde_expand that
returns a gdb::unique_xmalloc_ptr<char>. Change all callers of
tilde_expand to use gdb_rl_tilde_expand (even the couple of spots that
release it immediatly, for consistency). This simplifies a few callers.
The name gdb_tilde_expand is already taken by a home-made implementation
in gdbsupport/gdb_tilde_expand.{h.cc}. I wonder if we could just use
that one instead of readline's tilde_expand, but that's an orthogonal
question. I don't know how they differ, and I don't want to introduce
behavior changes in this patch.
Change-Id: I6d34eef19f86473226df4ae56d07dc01912e3131
Approved-By: Tom Tromey <tom@tromey.com>
f9e262e1cb