Make builtin init ifdefs consistent

Author: k0kubun

inits.c

@@ -102,10 +102,8 @@ rb_call_builtin_inits(void)
     BUILTIN(yjit);
     BUILTIN(nilclass);
     BUILTIN(marshal);
-#if USE_RJIT
     BUILTIN(rjit_c);
     BUILTIN(rjit);
-#endif
     Init_builtin_prelude();
 }
 #undef CALL

vm.c

@@ -4420,11 +4420,17 @@ Init_vm_objects(void)
     vm->frozen_strings = st_init_table_with_size(&rb_fstring_hash_type, 10000);
 }
 
-/* Stub for builtin function when not building YJIT units*/
+// Stub for builtin function when not building YJIT units
 #if !USE_YJIT
 void Init_builtin_yjit(void) {}
 #endif
 
+// Stub for builtin function when not building RJIT units
+#if !USE_RJIT
+void Init_builtin_rjit(void) {}
+void Init_builtin_rjit_c(void) {}
+#endif
+
 /* top self */
 
 static VALUE