Try harder not to use clock_gettime in verto-k5ev

We already define EV_USE_REALTIME to 0 to avoid the use of
clock_gettime() (to avoid depending on librt).  But in some build
environments libev can detect support for a monotonic clock, which
also results in using clock_gettime().  Define EV_USE_MONOTONIC to 0
as well to prevent this.

https://github.com/krb5/krb5/commit/fe285ec16b65ac6177a404baa635c1d09054dc81
Author: Greg Hudson <ghudson@mit.edu>
Commit: fe285ec16b65ac6177a404baa635c1d09054dc81
Branch: master
 src/util/k5ev/verto-k5ev.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)