Provide an option to send non-fatal machine-check errors to syslog (instead of the console)

[jtl]

Summary

Currently, all machine-check errors are logged to the console.

This change provides an option to send machine-check errors to the log instead of the console.

Also, it makes sure we don't double-log uncorrectable errors.

[jhb]

FreeBSD/sys/x86/x86/mca.c

305

I'm a bit leery of putting 1k on the stack. I have some old patches to use dedicated stacks for MC# (similar to what we do for NMI) which we might consider at some point and which would perhaps alleviate that worry.

[emaste]

ping