Fixed rebuildParsers.php (#686)

phpyacc is a sh file and should not be run via the php interpreter, but directly.

grammar/rebuildParsers.php

@@ -16,7 +16,7 @@
 $kmyacc = getenv('KMYACC');
 if (!$kmyacc) {
     // Use phpyacc from dev dependencies by default.
-    $kmyacc = PHP_BINARY . ' ' . __DIR__ . '/../vendor/bin/phpyacc';
+    $kmyacc = __DIR__ . '/../vendor/bin/phpyacc';
 }
 
 $options = array_flip($argv);