libbcc: Fix build with gcc 4.8+ 1/2

gcc 4.8+ exports __ashldi3, __divsi3, __fixdfdi, ... in libgcc.
Redefining them here causes linker errors.

Change-Id: I21e17608bc7ec0b13d56602c1169a2aaec121fcf
Signed-off-by: Bernhard Rosenkränzer <Bernhard.Rosenkranzer@linaro.org>

Conflicts:

	runtime/lib/ashldi3.c
	runtime/lib/lshrdi3.c
Fix build with gcc 4.8+ 2/2

Change-Id: I5b173405fcdcbb1cdda1fd98eb3407a1189dff84