fix mcsig(no)pass on arm Ubuntu10, arm thumb internal doc, improve
simulate_control_c
* new file docs/internals/arm_thumb_notes_gdbserver.txt
documentation about the subtilities of the thumb bit handling in gdbsrv.
* made the SIGFPE backtrace filtering less dependent on gdb/os/libc/...
* improved simulate_control_c : runs faster/less dependent on timeout value
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@11791