diff --git a/apdqc.install b/apdqc.install
index f021c94..718d173 100644
--- a/apdqc.install
+++ b/apdqc.install
@@ -172,7 +172,7 @@ function apdqc_requirements($phase) {
     if (empty($mysqlnd)) {
       exec('php --modules', $mysqlnd);
     }
-    if (empty($mysqlnd) && defined('PHP_BINARY') && !empty(PHP_BINARY)) {
+    if (empty($mysqlnd) && defined('PHP_BINARY') && !empty(constant('PHP_BINARY'))) {
       $php_bin_loc = PHP_BINARY;
       if (is_executable($php_bin_loc)) {
         exec($php_bin_loc . ' --modules', $mysqlnd);