Compiling without optimisations is silly, especially since some
warnings depend on the optimiser.  Use -O2.

Fortify adds warnings for unchecked I/O (among other things), which
seems to be a good idea for user-space code.  Enable that too.
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Len Brown <len.brown@intel.com>