Linux compiler fixes for Clang and GCC when using -Werror

[ckane]

Most of the changes here are {0,} -> {{0}} cleanups similar to what's done in https://github.com/Sysinternals/SysmonForLinux/pull/36/commits/ea0aa159ead783f71c7abd38b61a5b1aeed871fd.

As well, there is one missing cast (converting a signed to unsigned int type). I think that this is fine, but someone else might want to double check the potential values of prevLastEventOffset in this context. It was being tested against ULONG_MAX which threw a warning when the types didn't match.

[ckane]

Might as well drop a mention to https://github.com/Sysinternals/SysmonForLinux/pull/36 in here, as it contains the related changes to the Linux port of Sysmon.

[kesheldr]

This looks good - many thanks. As SysmonCommon is shared, I need to feed this back via a PR into the internal ADO first; when we have approval for that, I'll approve this one here.