Support C23 projects

Don't define true/false/bool when r3 is used by C23 projects
since C23 already has a bool type and predefined constants.

include/r3.h

@@ -12,6 +12,7 @@
 #include <string.h>
 #include <pcre.h>
 
+#if __STDC_VERSION__ <= 201710L
 #ifdef HAVE_STDBOOL_H
 #  include <stdbool.h>
 #elif !defined(bool) && !defined(__cplusplus)
@@ -20,6 +21,7 @@ typedef unsigned char bool;
 #  define false 0
 #  define true 1
 #endif
+#endif
 
 #include "str_array.h"
 #include "r3_slug.h"

include/str_array.h

@@ -10,6 +10,7 @@
 
 #include "memory.h"
 
+#if __STDC_VERSION__ <= 201710L
 #ifdef HAVE_STDBOOL_H
 #  include <stdbool.h>
 #elif !defined(bool) && !defined(__cplusplus)
@@ -18,6 +19,7 @@ typedef unsigned char bool;
 #  define false 0
 #  define true 1
 #endif
+#endif
 
 typedef struct _str_array {
   R3_VECTOR(r3_iovec_t) slugs;

src/match_entry.c

@@ -10,7 +10,6 @@
 #include <string.h>
 #include <pcre.h>
 #include <assert.h>
-#include <stdbool.h>
 
 #include "r3.h"