1 files changed, 2 insertions, 0 deletions

diff --git a/src/lisp.h b/src/lisp.h
index eed57048871..11337645e54 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -677,6 +677,8 @@ typedef unsigned char UCHAR;
 /* Return a glyph's face ID.  */
 #define GLYPH_FACE(glyph) (((glyph) >> 8) & ((1 << 24) - 1))
 
+/* The ID of the mode line highlighting face.  */
+#define GLYPH_MODE_LINE_FACE 1
 
 /* Data type checking */