tree 7d50c24b49cbbca5d7dabd6b082f7bb34fc60567
parent 4ba244cdbc61a9e36beded2f6cbea0c79dad60d0
author Tobias Schlüter <tobi@schlueters.de> 1613132207 +0900
committer Tobias Schlüter <Ruediger.Knippel@googlemail.com> 1613431836 +0900

Allow Unity build.

Two parts:
- missing include guard in solver_utils.h
- exclude schur_specializations from unity build.  This
  can only be done with cmake >= 3.16, so only allow
  unity build for these versions.

Cuts build time by 5 minutes with default settings.
libceres.a shrinks from 7549968 bytes to 7009696 bytes.

Change-Id: I833ac8266623da0e725cc2f07a6415b4fa72bc18