Includes:
- https://github.com/bitcoin-core/libmultiprocess/pull/165
- https://github.com/bitcoin-core/libmultiprocess/pull/173
- https://github.com/bitcoin-core/libmultiprocess/pull/172
These changes are needed to fix CI errors in #31802.
The changes can be verified by running test/lint/git-subtree-check.sh src/ipc/libmultiprocess as described in developer notes and lint instructions