diff --git a/panda/src/express/config_express.cxx b/panda/src/express/config_express.cxx
index 202cddfc5f..56ce275e7a 100644
--- a/panda/src/express/config_express.cxx
+++ b/panda/src/express/config_express.cxx
@@ -185,14 +185,18 @@ init_libexpress() {
 
   init_system_type_handles();
 
-  PandaSystem *ps = PandaSystem::get_global_ptr();
-
 #ifdef HAVE_ZLIB
+ {
+  PandaSystem *ps = PandaSystem::get_global_ptr();
   ps->add_system("zlib");
+ }
 #endif
 
 #ifdef HAVE_THREADS
+ {
+  PandaSystem *ps = PandaSystem::get_global_ptr();
   ps->add_system("threads");
+  }
 #endif
 }
 
diff --git a/panda/src/express/datagram.cxx b/panda/src/express/datagram.cxx
index b5fb570ba5..3cee779ca5 100644
--- a/panda/src/express/datagram.cxx
+++ b/panda/src/express/datagram.cxx
@@ -58,7 +58,7 @@ dump_hex(ostream &out) const {
   size_t num_bytes = get_length();
   for (size_t line = 0; line < num_bytes; line += 16) {
     char hex[12];
-    sprintf(hex, "%04x ", line);
+    sprintf(hex, "%04x ", ((unsigned int )line));
     out << hex;
 
     size_t p;