There's a merged pull request on the void-packages repository

monkey: move libdir to /usr/lib{32,64}/monkey
https://github.com/void-linux/void-packages/pull/29121

Description:
Those shared-objects are plugins for monkey,
its included debian rules also put them in /usr/lib/monkey.

While we're at it, fix --musl-mode argument.
(The actual code doesn't change if MUSL_CODE defined or not)

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#### General
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#### Have the results of the proposed changes been tested?
- [ ] I use the packages affected by the proposed changes on a regular basis and confirm this PR works for me
- [ ] I generally don't use the affected packages but briefly tested this PR

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