force the FreeBSD multithreaded core target to not register any target
for handling core dumps. This is analogous to the
'coreops_suppress_target' variable that GDB provides for suppressing the
default core dump target. KGDB will use this new variable so it can
provide its own core dump target that uses libkvm to work with vmcore
files.
- Adjust the long name and documentation of the FreeBSD multithreaded core
dump target so it better matches what GDB's core dump target uses.
MFC after: 1 week
Reviewed by: davidxu, marcel
23778603b0