UCX: compile errors with `--enable-timing` and `--enable-mem-debug`

[jsquyres]

Per https://www.mail-archive.com/devel@lists.open-mpi.org/msg20933.html, there are compile errors if one builds with UCX and --enable-timing or --enable-mem-debug.

These are apparently present on master and v4.0.x.

[artpol84]

Thank you, @jsquyres
@karasevb please have a look. Start from "--enable-timings" as this is your code and should be easier to attack.

[karasevb]

Refs #6072 relatively errors with --enable-timing

[jsquyres]

See also #7926 and #7927.