diff --git a/src/vim.h b/src/vim.h
index 1cf7648..eb31217 100644
--- a/src/vim.h
+++ b/src/vim.h
@@ -953,6 +953,7 @@
 # define HL_TRANS_CONT	0x10000 // transparent item without contains arg
 # define HL_CONCEAL	0x20000 // can be concealed
 # define HL_CONCEALENDS	0x40000 // can be concealed
+# define HL_INCLUDED_TOPLEVEL 0x80000 // toplevel item in included syntax, allowed by contains=TOP
 #endif
 
 // Values for 'options' argument in do_search() and searchit()