Inject architecture specific flags: - For amd64 and i386 add -mtune=generic and -msse3, - use -fsigned-char for all architectures and place it in the very beginning of CFLAGS, otherwise test fail on architecrures with unsigned char signedness - Change -O9 to -O3 because -O levels higher than 3 have no effect - Append CFLAGS and LDFLAGS instead of hardcoding the values, this way the hardening flags are set correctly
