option('gnustl', type: 'feature',
       value: 'auto',
       description: 'Use gnustl for a c++ library implementation (only used on Android)')
option('neon', type: 'combo',
       choices: ['no', 'yes', 'auto', 'runtime'],
       description: 'Enable NEON optimisations')
option('inline-sse', type: 'boolean',
       value: true,
       description: 'Enable inline SSE/SSE2 optimisations (i.e. assume CPU supports SSE/SSE2)')