Add a test case for a memory leak in xhprof_enable()

See <phacility#60>.

extension/tests/xhprof_012.phpt

@@ -0,0 +1,32 @@
+--TEST--
+XHProf: Memory Leak in Ignored Functions
+Author: epriestley
+--FILE--
+<?php
+
+$old = memory_get_usage();
+
+// This test covers a leak where the ignored function list would not be
+// deallocated properly after a new call to xhprof_enable().
+
+$large = str_repeat('x', (1024 * 1024 * 16));
+xhprof_enable(0, array('ignored_functions' => array($large)));
+xhprof_disable();
+unset($large);
+
+xhprof_enable();
+xhprof_disable();
+
+$new = memory_get_usage();
+
+$missing = ($new - $old);
+
+if ($missing >= (1024 * 1024 * 16)) {
+  echo "LEAKED A LOT OF MEMORY\n";
+} else {
+  echo "DID NOT LEAK A LOT OF MEMORY\n";
+}
+
+?>
+--EXPECTF--
+DID NOT LEAK A LOT OF MEMORY