Unconditionally add version info to the build header

[tschaub]

This reworks the changes in #2442 so we always include the version info, regardless of whether the module is run as main or not. This also addresses a few lint related issues.

[marcjansen]

This looks good to me.

Please merge & thanks.

[probins]

I've been thinking some more about this build header, and there are several issues with having hard-coded text. It's not really appropriate, or not entirely appropriate, in the case where people want to compile their own code in with OL, as the text only applies to the OL bit, not the app code bit. For this, it would be more flexible if the output wrapper were used as before, or perhaps better the new output wrapper file. I would also like the ability to specify the output file in the config compile options rather than in the cmd line; in this case, you would have to use the output wrapper anyway, as the header would never be added. There's also the related question of the license, which should also be added at some point.