diff --git a/src/vim.h b/src/vim.h
index a0ee0d6..7ba728a 100644
--- a/src/vim.h
+++ b/src/vim.h
@@ -2544,12 +2544,14 @@
 #define TFN_NO_DEREF	0x08	// do not dereference a Funcref
 #define TFN_READ_ONLY	0x10	// will not change the var
 #define TFN_NO_DECL	0x20	// only used for GLV_NO_DECL
+#define TFN_COMPILING	0x40	// only used for GLV_COMPILING
 
 // Values for get_lval() flags argument:
 #define GLV_QUIET	TFN_QUIET	// no error messages
 #define GLV_NO_AUTOLOAD	TFN_NO_AUTOLOAD	// do not use script autoloading
 #define GLV_READ_ONLY	TFN_READ_ONLY	// will not change the var
 #define GLV_NO_DECL	TFN_NO_DECL	// assignment without :var or :let
+#define GLV_COMPILING	TFN_COMPILING	// variable may be defined later
 
 #define DO_NOT_FREE_CNT 99999	// refcount for dict or list that should not
 				// be freed.