diff --git a/setup.h.in b/setup.h.in
index ab4f865fc2..c6090c0bcb 100644
--- a/setup.h.in
+++ b/setup.h.in
@@ -1103,7 +1103,7 @@
  * with the jpeg headers unless HAVE_BOOLEAN is defined).  */
 #undef HAVE_BOOLEAN
 
-/* Define is the header pbt.h is missing.  */
+/* Define if the header pbt.h is missing.  */
 #undef NEED_PBT_H
 
 #endif /* __WIN32__ */