use gcc 4.9 toolchain

Change-Id: I3ef3b27cb1eae273ebd338a9a3659f42a1f5e53d
use 4.8 toolchain for arm-eabi

Change-Id: If3f0cf4f14d18a8e6406aa32993d620a3855068f
use gcc 4.9 toolchain

Change-Id: I3e21df746a0cf90200e7549bfe8db972ffd6d3e1