Made code (mostly) follow C99

connect4.c

@@ -30,7 +30,7 @@
 #include "types.h"
 #include "ui.h"
 
-#define VERSION 0.3.0
+#define VERSION 0.3.1
 
 #ifndef GITHASH
 #define FULLVERSION VERSION
@@ -48,7 +48,11 @@ extern char _binary_LICENSE_start[];
 extern char _binary_LICENSE_end[];
 #endif /* ! NO_OPTIONS */
 
-int main( [[maybe_unused]] int argc, [[maybe_unused]] char *argv[] ){
+int main(
+#ifndef NO_OPTIONS // [[maybe_unused]] is unsupported in C99, so this will do
+	int argc, char *argv[]
+#endif /* ! NO_OPTIONS */
+){
 	// Initialise variables
 	board_t playboard = {
 		.player = 0,

makefile

@@ -7,7 +7,7 @@ ARCH = native
 O = s
 
 # Flags for the compiler
-FLAGS  = -std=c23
+FLAGS  = -std=gnu99
 FLAGS += -O$(O)
 FLAGS += -march=$(ARCH)
 # Only override gcc default tuning if specified in make command line

types.h

@@ -2,6 +2,7 @@
 #pragma once
 
 #include <stdint.h>
+#include <stdbool.h>
 #include <limits.h>
 #include "config.h"