--- hdf/test/mgr.c.orig	2020-03-03 10:40:50.000000000 -0700
+++ hdf/test/mgr.c	2021-04-05 19:46:00.000000000 -0700
@@ -29,6 +29,10 @@
 #include "tproto.h"
 #include "mfgr.h"
 
+#ifdef H4_HAVE_LIBSZ
+extern void test_mgr_szip();
+#endif
+
 /* Local pre-processor macros */
 #define XDIM    0
 #define YDIM    1