MFC r215679:

MFC r215679:
Add the ability for GDB to printout the thread name along with other thread
specific informations.
In order to achieve that, for both on-line debugging and core analysis,
a new member to PT_LWPINFO ptrace(2) interface is added and a new
ELF note (NT_THRMISC) as well.

Sponsored by:	Sandvine Incorporated

git-svn-id: svn://svn.freebsd.org/base/stable/8@216734 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f