patch 7.4.2121
Problem:    No easy way to check if lambda and closure are supported.
Solution:   Add the +lambda feature.
diff --git a/src/version.c b/src/version.c
index 7e8ca16..4af1468 100644
--- a/src/version.c
+++ b/src/version.c
@@ -304,6 +304,11 @@
 #else
 	"-keymap",
 #endif
+#ifdef FEAT_EVAL
+	"+lambda",
+#else
+	"-lambda",
+#endif
 #ifdef FEAT_LANGMAP
 	"+langmap",
 #else
@@ -759,6 +764,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2121,
+/**/
     2120,
 /**/
     2119,