Sync internal and external versions. This fixed a problem that

gdb inserts wrong kind of break points at ARM/THUMB boundaries.
The patch is a backport of 3 upstream patches.

Change-Id: I21f66152d2a06bb5f2b83573b6296bdcf5fcf0c7
http://www.cygwin.com/ml/gdb-cvs/2010-03/msg00030.html
http://www.cygwin.com/ml/gdb-cvs/2010-08/msg00190.html
http://www.cygwin.com/ml/gdb-cvs/2011-04/msg00002.html