Makefile: adding config variable for Os/O2/O3 compilation
fix build errors with -O2 flag
how about some -o2
fix wrong build flags setup and add more build flags

Conflicts:
	Makefile
Makefile: improve build flags

Conflicts:
	arch/arm/Makefile
Makefile: enable graphite loop optimization
Makefile: adding config variable for Ofast compilation
defconfig update
Makefile: improved build flags
Makefile: use old build flags and added -fgraphite flag. performace are higher