Revert "Revert "ota: Make sure we don't install on top of an incompatible system""

This should be fixed now.

This reverts commit 5875e3437d368411b986de70d3a844b27d78531f.

Change-Id: Ie102ff6ecb08bff80c83654a490fd18248d23086
core: arm: Add support for GCC 4.8 and 4.9

Change-Id: I96bffffb4b0e16ef5bcedc85dedc70ca3dc2182f
core: arm: Use -O3 optimization inside TARGET_arm_CFLAGS

Change-Id: I224b62b3dada874d00a90258a1dcffcea09bc029