DISABLE_BIT       607 ruby.c         #define UNSET_WHEN_DISABLE(bit) UNSET_WHEN(#bit, DISABLE_BIT(bit), str, len)
DISABLE_BIT       620 ruby.c         #define SET_WHEN_DISABLE(bit) SET_WHEN(#bit, DISABLE_BIT(bit), str, len)
DISABLE_BIT      1211 ruby.c             if (!(opt->disable & DISABLE_BIT(rubyopt)) &&
DISABLE_BIT      1312 ruby.c             ruby_init_gems(!(opt->disable & DISABLE_BIT(gems)));