When using ninja to build there is an error due to duplicate targets, due to the files generated in setup_fgfs_embedded_resources()
from SetupFGFSEmbeddedResources.cmake
, which is called multiple times.
[1] http://package22.nyi.freebsd.org/data/112amd64-default-PR235259PR235474PR235507/2019-02-05_16h51m55s/logs/errors/flightgear-2018.3.2.log
I had a similar problem on windows, and I commented out setup_fgfs_embedded_resources in Main/CmakeLists.txt to get rid of the problem.
Resolved on branch 'next'