Add minimum required PHP version to run-tests.php

This integrates a simple minimum PHP version info in the tool and to
also define the minimum version that the tool syntax should support.

diff --git a/run-tests.php b/run-tests.php
index a8dbd81c38ace7a1d7f5a449da7c22d4a6cdf4a0..58d10967a19ce468973b890e14ba1ea2541fdfbf 100755 (executable)
--- a/run-tests.php
+++ b/run-tests.php
@@ -29,6 +29,8 @@
 
 /* Let there be no top-level code beyond this point:
  * Only functions and classes, thanks!
+ *
+ * Minimum required PHP version: 7.0.0
  */
 
 /**