diff --git a/tests/scripts/test-ref-configs.pl b/tests/scripts/test-ref-configs.pl
index d1cc924..c3d1426 100755
--- a/tests/scripts/test-ref-configs.pl
+++ b/tests/scripts/test-ref-configs.pl
@@ -57,7 +57,7 @@
     system( "cp configs/$conf $config_h" )
         and abort "Failed to activate $conf\n";
 
-    system( "make" ) and abort "Failed to build: $conf\n";
+    system( "make CFLAGS='-Os -Werror'" ) and abort "Failed to build: $conf\n";
     system( "make test" ) and abort "Failed test suite: $conf\n";
 
     if( $args )