[PHP 8.4] Add CURL_HTTP_VERSION_3(ONLY) constants

If the underlying Curl build supports it, setting the HTTP version
should be theoretically possible. The availability of the constants
do not guarantee the feature support, so declaring them in the
polyfill should be same and effective.

 - PR that added constants: [php-src#15350](php/php-src#15350)
 - libcurl doc on `CURLOPT_HTTP_VERSION`](https://curl.se/libcurl/c/CURLOPT_HTTP_VERSION.html)
 - [PHP.Watch: HTTP/3 Request with PHP Curl Extension](https://php.watch/articles/php-curl-http3)
 - Codex for [`CURL_HTTP_VERSION_3`](https://php.watch/codex/CURL_HTTP_VERSION_3) and [`CURL_HTTP_VERSION_3ONLY`](https://php.watch/codex/CURL_HTTP_VERSION_3ONLY)

Fixes GH-488.

README.md

@@ -6,6 +6,7 @@ This component provides features added to PHP 8.4 core:
 - [`mb_ucfirst` and `mb_lcfirst`](https://wiki.php.net/rfc/mb_ucfirst)
 - [`array_find`, `array_find_key`, `array_any` and `array_all`](https://wiki.php.net/rfc/array_find)
 - [`Deprecated`](https://wiki.php.net/rfc/deprecated_attribute)
+- `CURL_HTTP_VERSION_3` and `CURL_HTTP_VERSION_3ONLY` constants
 
 More information can be found in the
 [main Polyfill README](https://github.com/symfony/polyfill/blob/main/README.md).

bootstrap.php

@@ -15,6 +15,14 @@
     return;
 }
 
+if (defined('CURL_VERSION_HTTP3') || PHP_VERSION_ID < 80200 && function_exists('curl_version') && curl_version()['version'] >= 0x074200) { // libcurl >= 7.66.0
+    define('CURL_HTTP_VERSION_3', 30);
+
+    if (defined('CURLOPT_SSH_HOST_PUBLIC_KEY_SHA256')) { // libcurl >= 7.80.0 (7.88 would be better but is slow to check)
+        define('CURL_HTTP_VERSION_3ONLY', 31);
+    }
+}
+
 if (!function_exists('array_find')) {
     function array_find(array $array, callable $callback) { return p\Php84::array_find($array, $callback); }
 }