Show source git hash used during compilation with --version option

[ceblanton]

Is your feature request related to a problem? Please describe.
To help debug user issues, it's helpful to know exactly which source was used during the compilation. For cases where the source code is still available, one can simply check the repository. However, if the tools were installed someplace else, it can be harder to determine which source code was used. It would also be helpful to record whether the git repository used was clean or contained uncommited changes.

Describe the solution you'd like
The tools to display this provenance information using the --version option:

If compiled from a clean repository:

<command>: <package_name>(<git_hash>) <commit_date>

If compiled from a uncommited repository:

<command>: <package_name>(Uncommitted) <build_date>

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
Some of this information is already captured in the automake-generated config.h file. Each tool would then need to include this file and make it available from the --version option.

[ceblanton]

This could report the configure.ac version primarily, in addition to the git hash