Makefile: Compile with -Ofast

Signed-off-by: Zhao Wei Liew <zhaoweiliew@gmail.com>
Makefile: Compile with graphite optimizations

Signed-off-by: Zhao Wei Liew <zhaoweiliew@gmail.com>
Makefile: Compile with misc optimization flags globally

Signed-off-by: Zhao Wei Liew <zhaoweiliew@gmail.com>