tree 81081e5ec26ef87585cd958d851971941fef2736
parent 9671d850e6b4498eb483b373024f647c2f17305c
author Alex Stewart <alexs.mac@gmail.com> 1529178557 +0100
committer Sameer Agarwal <sameeragarwal@google.com> 1529536857 +0000

Refactor Ceres threading option configuration.

- Previously we had separate variables for each of the threading
  backends, each of which were made mutually exclusive via
  cmake_dependent_option().  This has unfortunate side-effects when
  trying to disable options if they are not currently enabled, in which
  case they are not defined.
- As all the threading options are mutually exclusive, this replaces
  all threading option variables with a single variable: CERES_THREADS,
  which is constrained to take the value of only the available threading
  backends.

Change-Id: I0822eefbac9a30772907b7732add365b37cc8ca0