diff --git a/src/SPC/builder/extension/grpc.php b/src/SPC/builder/extension/grpc.php
index fe13a76a..f2f36c16 100644
--- a/src/SPC/builder/extension/grpc.php
+++ b/src/SPC/builder/extension/grpc.php
@@ -61,5 +61,6 @@ class grpc extends Extension
     {
         $env = parent::getSharedExtensionEnv();
         $env['CPPFLAGS'] = $env['CXXFLAGS'];
+        return $env;
     }
 }