diff --git a/src/ex_docmd.c b/src/ex_docmd.c
index e51f849..be0e346 100644
--- a/src/ex_docmd.c
+++ b/src/ex_docmd.c
@@ -1570,7 +1570,7 @@
 #endif
 }
 
-#if defined(FEAT_EVAL) || defined(PROT)
+#if defined(FEAT_EVAL) || defined(PROTO)
 /*
  * Get the next line source line without advancing.
  */