Use bl instead of blx to support interworking properly.
Clean up useless declaration in thread_private.h

Change-Id: Ie7bcdc7195a3fcbcd09a95f73b0c49e8897ad50b
sys/personality.h: include <sys/cdefs.h>

Change-Id: Ia3fa558a38e0cffe5287bc454e85d5d3bdaa6ba1
Fix abort(3) to raise SIGABRT rather than causing SIGSEGV.

tgkill() needs the .save stack unwinding directive to get the complete
stack trace.

BUG: https://code.google.com/p/android/issues/detail?id=16672

Change-Id: Ifb447dca2147a592c48baf32769dfc175d8aea72