Convert a bunch of constant strings in C to unicode.
diff --git a/Modules/zlibmodule.c b/Modules/zlibmodule.c
index badc090..fd6c0b7 100644
--- a/Modules/zlibmodule.c
+++ b/Modules/zlibmodule.c
@@ -1039,7 +1039,7 @@
     PyModule_AddIntConstant(m, "Z_SYNC_FLUSH", Z_SYNC_FLUSH);
     PyModule_AddIntConstant(m, "Z_FULL_FLUSH", Z_FULL_FLUSH);
 
-    ver = PyString_FromString(ZLIB_VERSION);
+    ver = PyUnicode_FromString(ZLIB_VERSION);
     if (ver != NULL)
 	PyModule_AddObject(m, "ZLIB_VERSION", ver);