Fix errors and a warning

* PHP < 8.0 took a `char*` as `php_json_decode` input, whereas newer
  versions take a const char * so ifdef around this.

* Fix compilation errors due to `false` not being defined. So as to make
  a minimal change we can just use 0 and 1

library.c

@@ -2686,14 +2686,22 @@ fail:
 PHP_REDIS_API int
 redis_deserialize_vgetattr_reply(zval *zret, const char *str, size_t len) {
 #ifdef HAVE_REDIS_JSON
-    if (php_json_decode(zret, str, len, 1, PHP_JSON_PARSER_DEFAULT_DEPTH)
-                        == FAILURE)
+    #if PHP_VERSION_ID < 80000
+        #define PHP_JSON_IN(s) ((char*)s)
+    #else
+        #define PHP_JSON_IN(s) (s)
+    #endif
+
+    if (php_json_decode(zret, PHP_JSON_IN(str), len, 1,
+                        PHP_JSON_PARSER_DEFAULT_DEPTH) == FAILURE)
     {
         php_error_docref(NULL, E_WARNING, "Failed to deserialize attributes");
         return FAILURE;
     }
 
     return SUCCESS;
+
+    #undef PHP_JSON_IN
 #else
     php_error_docref(NULL, E_WARNING,
         "PhpRedis is not compiled with JSON support");

redis_commands.c

@@ -7043,8 +7043,8 @@ int
 redis_vlinks_cmd(INTERNAL_FUNCTION_PARAMETERS, RedisSock *redis_sock,
                  char **cmd, int *cmd_len, short *slot, void **ctx)
 {
-    zend_bool withscores = false;
     smart_string cmdstr = {0};
+    zend_bool withscores = 0;
     zend_string *key;
     zval *member;