SET_WHEN          149 debug.c            SET_WHEN("gc_stress", *ruby_initial_gc_stress_ptr);
SET_WHEN          150 debug.c            SET_WHEN("core", ruby_enable_coredump);
SET_WHEN          620 ruby.c         #define SET_WHEN_DISABLE(bit) SET_WHEN(#bit, DISABLE_BIT(bit), str, len)
SET_WHEN          633 ruby.c         #define SET_WHEN_DUMP(bit) SET_WHEN(#bit, DUMP_BIT(bit), str, len)