Fix another define redifinition (15.10 01:59)
#include "../addons/json.h"
#endif
#if defined(FLECS_EXPR) || defined(FLECS_META_C)
+#ifndef FLECS_META
#define FLECS_META
#endif
+#endif
#ifdef FLECS_UNITS
#ifdef FLECS_NO_UNITS
#error "FLECS_NO_UNITS failed: UNITS is required by other addons"
