diff --git a/configure.py b/configure.py
index 4d13adeed0d704..1b5110fbeb925b 100755
--- a/configure.py
+++ b/configure.py
@@ -396,7 +396,7 @@
     action='store',
     dest='shared_uvwasi_libname',
     default='uvwasi',
-    help='alternative lib name to link to [default: %default]')
+    help='alternative lib name to link to [default: %(default)s]')
 
 shared_optgroup.add_argument('--shared-uvwasi-libpath',
     action='store',