diff --git a/Include/unicodeobject.h b/Include/unicodeobject.h
index 32002e06581..87e01af1736 100644
--- a/Include/unicodeobject.h
+++ b/Include/unicodeobject.h
@@ -58,6 +58,14 @@ Copyright (c) Corporation for National Research Initiatives.
 
 /* --- Internal Unicode Format -------------------------------------------- */
 
+/* FIXME: MvL's new implementation assumes that Py_UNICODE_SIZE is
+   properly set, but the default rules below doesn't set it.  I'll
+   sort this out some other day -- fredrik@pythonware.com */
+
+#ifndef Py_UNICODE_SIZE
+#error Must define Py_UNICODE_SIZE
+#endif
+
 /* experimental UCS-4 support.  enable at your own risk! */
 #undef USE_UCS4_STORAGE
 #if Py_UNICODE_SIZE == 4
diff --git a/PC/config.h b/PC/config.h
index 3b81a450a4d..341f9bbbc63 100644
--- a/PC/config.h
+++ b/PC/config.h
@@ -484,6 +484,15 @@ typedef unsigned long uintptr_t;
 /* Define if you want to use the GNU readline library */
 /* #define WITH_READLINE 1 */
 
+/* Define if you want to have a Unicode type. */
+#define Py_USING_UNICODE
+
+/* Define as the integral type used for Unicode representation. */
+#define PY_UNICODE_TYPE unsigned short
+
+/* Define as the size of the unicode type. */
+#define Py_UNICODE_SIZE SIZEOF_SHORT
+
 /* Define if you want cycle garbage collection */
 #define WITH_CYCLE_GC 1