diff --git a/src/spell.c b/src/spell.c
index 66ccecb..fd7e4e1 100644
--- a/src/spell.c
+++ b/src/spell.c
@@ -317,7 +317,7 @@
 
 /* Type used for indexes in the word tree need to be at least 4 bytes.  If int
  * is 8 bytes we could use something smaller, but what? */
-#if SIZEOF_INT > 3
+#if VIM_SIZEOF_INT > 3
 typedef int idx_T;
 #else
 typedef long idx_T;