Fix several incompatibilities with RHEL

[tfiedor]

1. Fix issue with libunwind not being present on some systems,
2. Fix minor issue with forgotten scripts.
3. Add forgotten option to formatting strings.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 98.77%. Comparing base (5127326) to head (78082de).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## devel #194 +/- ## ======================================= Coverage 98.77% 98.77% ======================================= Files 144 144 Lines 9827 9827 ======================================= Hits 9707 9707 Misses 120 120 ``` | [Flag](https://app.codecov.io/gh/Perfexionists/perun/pull/194/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Perfexionists) | Coverage Δ | | |---|---|---| | [coverage-3.10](https://app.codecov.io/gh/Perfexionists/perun/pull/194/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Perfexionists) | `98.75% <ø> (ø)` | | | [coverage-3.11](https://app.codecov.io/gh/Perfexionists/perun/pull/194/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Perfexionists) | `98.73% <ø> (+0.01%)` | :arrow_up: | | [coverage-3.12](https://app.codecov.io/gh/Perfexionists/perun/pull/194/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Perfexionists) | `98.72% <ø> (ø)` | | | [coverage-3.9](https://app.codecov.io/gh/Perfexionists/perun/pull/194/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Perfexionists) | `98.76% <ø> (+0.01%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Perfexionists#carryforward-flags-in-the-pull-request-comment) to find out more.

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