Update .gitignore

Signed-off-by: Dan Trifan <jimsth@gmail.com>
scripts: remove the "+" symbol from kernel version string

Signed-off-by: Dan Trifan <jimsth@gmail.com>
makefile: refactor ccache use

Signed-off-by: Dan Trifan <jimsth@gmail.com>
Makefile: optimizations from bricked

Signed-off-by: Dan Trifan <jimsth@gmail.com>
arch:arm:Makefile: enable pipe compiling

Signed-off-by: Dan Trifan <jimsth@gmail.com>