lower C/C++ version requirement

Makefile

@@ -7,8 +7,8 @@ MAKEFILE_PATH := $(patsubst %/,%,$(dir $(abspath $(firstword $(MAKEFILE_LIST))))
 
 DEBUG = -g
 
-CSTD += -std=gnu23
-CXXSTD += -std=gnu++23
+CSTD += -std=gnu11
+CXXSTD += -std=gnu++14
 
 CFLAGS += -Wall -Werror -Wfatal-errors
 CFLAGS += -Wno-error=unused-function

include/state.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <stdint.h>
+#include <stdbool.h>
 
 #ifdef __cplusplus
 extern "C" {

src/unparse.c

@@ -1,4 +1,5 @@
 #include <math.h>
+#include <stdbool.h>
 
 #include "unparse.h"