Update host linux toolchain to gcc 4.8

This patch ensures the build system uses the prebuilt gcc-4.8 toolchain
when building host Linux binaries, instead of the gcc-4.6 one.

Change-Id: I7b449650714ba4314a780827e0243f2af40ec82c
Signed-off-by: Chet Kener <Cl3Kener@gmail.com>