SW-382: fixed compiler warning

LTA/LTAIngest/LTAIngestServer/LTAIngestTransferServer/bin/md5a32bc/adler32.c

@@ -81,7 +81,7 @@ uLong adler32(adler, buf, len)
     }
 
     /* initial Adler-32 value (deferred check for len == 1 speed) */
-    if (buf == Z_NULL)
+    if (buf == (void*)Z_NULL)
         return 1L;
 
     /* in case short lengths are provided, keep it somewhat fast */