Merge Helgrind from branches/YARD into the trunk.  Also includes some
minor changes to make stack unwinding on amd64-linux approximately
twice as fast as it was before.



git-svn-id: svn://svn.valgrind.org/valgrind/trunk@8707 a5019735-40e9-0310-863c-91ae7b9d1cf9
26 files changed