Use master branch for isl

Signed-off-by: Paul Beeler <pbeeler80@gmail.com>
Update default gcc to 4.8.5

Signed-off-by: Paul Beeler <pbeeler80@gmail.com>
Update README.md
Update README.md:

Link kernel asm headers to /usr/include/asm
Revert "Update README.md:"

This reverts commit eb163a714694b915e1619589b25efddda0ba8bde.
manifest: sync local build-scripts repository

Change-Id: I58df7f92e7b19b85ab20a6b99d1c5f118d8b8953