Merge branch 'issue/cleanup-ug-undefs' into 'master'
Reduce the number of undef statements in the ug_undefs.hh
Closes #120 (closed)
See merge request !504 (merged)
(cherry picked from commit 26abee0a)
c841a87d Reduce the number of undef statements in the ug_undefs.hh dae0ddcb Preserve order of undefs d9a0e464 Do not remove undef of DUNE_UGINCLUDES_HH