diff --git a/src/conf_post.h b/src/conf_post.h
index 683a96f936..dbe5befcf9 100644
--- a/src/conf_post.h
+++ b/src/conf_post.h
@@ -54,10 +54,10 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
     ((v) < __GNUC__ + ((w) < __GNUC_MINOR__ + ((x) <= __GNUC_PATCHLEVEL__)))
 #endif
 
-/* The type of bool bitfields.  Needed to compile Objective-C with
-   standard GCC.  It was also needed to port to pre-C99 compilers,
-   although we don't care about that any more.  */
-#if NS_IMPL_GNUSTEP
+/* The type of bool bitfields.  Preferably bool for better debugging,
+   bu unsigned int on MS-Windows to avoid struct bloat, and unsigned
+   int for Objective-C with standard GCC.  */
+#if defined DOS_NT || NS_IMPL_GNUSTEP
 typedef unsigned int bool_bf;
 #else
 typedef bool bool_bf;