Fix --disable-unicode compilation problems.
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 04a0611..fd7f69f 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -22,6 +22,11 @@
 disguised Unix interface).  Refer to the library manual and\n\
 corresponding Unix manual entries for more information on calls.");
 
+#ifndef Py_USING_UNICODE
+/* This is used in signatures of functions. */
+#define Py_UNICODE void
+#endif
+
 #if defined(PYOS_OS2)
 #define  INCL_DOS
 #define  INCL_DOSERRORS