Michał Kępień 3506a22fb7 Improve reporting for mutex errors ...

Replace all uses of RUNTIME_CHECK() in lib/isc/include/isc/mutex.h with
ERRNO_CHECK(), in order to improve error reporting for any mutex-related
run-time failures (by augmenting error messages with file/line/caller
information and the error string corresponding to errno).

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isc

Improve reporting for mutex errors

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.clang-format

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