clang sanitizers (memory, address, etc)

[squid at peralex.com]

Good day,

I'm running current, and I've managed to compile, but not link some code
using -sanitizer=memory.  The linker is missing some symbols
(__msan_memcpy and others), and I can't find the appropriate library.
I've found no mention of anybody using the sanitizers on FreeBSD though.

Are those symbols available for FreeBSD, and if so, what library are
they in?  Or are the sanitizers only available for Linux?

Thanks
Mark