Use fallback if git_version fails

[jprendes]

Fix #341

[jsturtevant]

This is probably fine as a work around. Is there any reason to ship the source code with a simple file that includes the git commit?

[jprendes]

When a release is created GH creates a tar file with the source. IIUC that happens automatically.
Are you suggesting we hardcode the commit id in there?

[jsturtevant]

I was thinking something similar to https://git-scm.com/book/en/v2/Customizing-Git-Git-Attributes#_exporting_your_repository

[jprendes]

Hm, I was thinking of something on the line of include_str("../LAST_COMMIT"). However, that means that a missing LAST_COMMIT file would result in a compile error. This would work fine for runwasi itself but would break dependant projects without a LAST_COMMIT file. It would be simpler if there was a option_include_str macro!

Also that approach would not reflect any local modifications that could have been done, so it could be missleading if used for debugging. We could append a .a to indicate the id comes from an archive and can't be 100% trusted, in a similar fashion to what we do now appending .m to indicate a dirty repo.

I personally prefer a <none> or <unknown> tag as is the case now.

[jsturtevant]

I personally prefer a or tag as is the case now.

This make sense to me based on your feedback above

[Mossaka]

lgtm!

[devigned]

lgtm!