ext/extlz4.h in extlz4-0.3.1 vs ext/extlz4.h in extlz4-0.3.2

@@ -4,19 +4,24 @@
 #include <ruby.h>
 #include <ruby/thread.h>
 #include <stdarg.h>
 #include <stdlib.h>
 #include <errno.h>
+#include <stdbool.h>
 
 #ifndef RB_OBJ_FROZEN
 #   define RB_OBJ_FROZEN    OBJ_FROZEN
 #endif
 
 extern VALUE extlz4_mLZ4;      /* module LZ4 */
 extern VALUE extlz4_eError;    /* class LZ4::Error < ::RuntimeError */
 
 extern void extlz4_init_blockapi(void);
 extern void extlz4_init_frameapi(void);
+
+#ifndef RB_EXT_RACTOR_SAFE
+# define RB_EXT_RACTOR_SAFE(FEATURE) ((void)(FEATURE))
+#endif
 
 #define AUX_FUNCALL(RECV, METHOD, ...)                          \
     ({                                                          \
         VALUE args__[] = { __VA_ARGS__ };                       \
         rb_funcall2((RECV), (METHOD),                           \