Fix compilation error with C23

hsbt · hsbt · commit a0c2d7c1187e · 2024-10-08T13:05:38.000+09:00
This fallback already defined at ruby/internal/stdbool.h
diff --git a/ext/json/ext/generator/generator.h b/ext/json/ext/generator/generator.h
@@ -6,9 +6,7 @@
 
 #include "ruby.h"
 
-#ifdef HAVE_STDBOOL_H
-#include <stdbool.h>
-#else
+#ifndef RBIMPL_STDBOOL_H
 /* This is the fallback definition from Ruby 3.0.5. */
 typedef unsigned char _Bool
 #define bool _Bool
