This patch add new environment variables to control compiler cache.
Works as follow: If persistent cache is set driver check if NEO_CACHE_DIR
is set. If not then driver checks XDG_CACHE_HOME - If exists
then driver create neo_compiler_cache folder, if
not then driver checks HOME directory. If each NEO_CACHE_DIR,
XDG_CACHE_HOME and HOME are not set then compiler cache is disabled.
Current support is for Linux only.
Signed-off-by: Diedrich, Kamil <kamil.diedrich@intel.com>
Related-To: NEO-4262
Diedrich, Kamil