binutils-2.20.1: import several patches from Debian

Import several patches from Debian to improve --no-add-needed handling
vs. weak symbols and branching to weak symbols on arm.

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>