diff --git a/lib/config-win32.h b/lib/config-win32.h
index 3d7892fec..00191fe4c 100644
--- a/lib/config-win32.h
+++ b/lib/config-win32.h
@@ -399,6 +399,9 @@
 /* Define to the size of `short', as computed by sizeof. */
 #define SIZEOF_SHORT 2
 
+/* Define to the size of `long', as computed by sizeof. */
+#define SIZEOF_LONG 4
+
 /* Define to the size of `size_t', as computed by sizeof. */
 #if defined(_WIN64)
 #  define SIZEOF_SIZE_T 8
diff --git a/lib/config-win32ce.h b/lib/config-win32ce.h
index eb444c585..28a15f2a1 100644
--- a/lib/config-win32ce.h
+++ b/lib/config-win32ce.h
@@ -346,6 +346,9 @@
 /* The size of `short', as computed by sizeof. */
 #define SIZEOF_SHORT 2
 
+/* Define to the size of `long', as computed by sizeof. */
+#define SIZEOF_LONG 4
+
 /* The size of `size_t', as computed by sizeof. */
 #if defined(_WIN64)
 #  define SIZEOF_SIZE_T 8