-  git_describe(-Version, +Options) is semidet
 - Describe the running version based on GIT tags and hashes.
Options:
- match(+Pattern)
 - Only use tags that match Pattern (a Unix glob-pattern; e.g.
V*) 
- directory(Dir)
 - Provide the version-info for a directory that is part of
a GIT-repository.
 
- commit(+Commit)
 - Describe Commit rather than 
HEAD 
- See also
 - - git describe