Put Git revision in executable or library

Traceability of a binary artifact such as an executable or library can be improved by writing information about the Git repository status into the artifact itself. This is a finer-grained implementation of the version number we are accustomed to seeing in the command line interface of executables. This example doesn’t cover every possible thing to be traced, for example non-version controlled artifacts that are linked in. This example just covers the Git repo of the current CMake project. Nonetheless, those needing more advanced traceability can build upon this example.

Usually for easier reuse across projects, we put this in a separate CMake script file like gitrev.cmake and include it from the main CMake project.

See the example in Fortran2018-examples repo.