added system() param-out

Author: staabm

stubs/core.stub

@@ -86,6 +86,8 @@ function similar_text(string $string1, string $string2, float &$percent = null)
  */
 function exec(string $command, &$output, &$result_code): string|false {}
 
+/** @param-out int $result_code */
+function system(string $command, &$result_code): string|false {}
 
 /**
  * @template T

tests/PHPStan/Analyser/data/param-out.php

@@ -333,3 +333,9 @@ function fooExec() {
 	assertType('list<string>', $output);
 	assertType('int', $exitCode);
 }
+
+function fooSystem() {
+	system("my cmd", $exitCode);
+
+	assertType('int', $exitCode);
+}