diff --git a/upb/bindings/lua/upb.c b/upb/bindings/lua/upb.c
index 87b39e647a..9629314d6d 100644
--- a/upb/bindings/lua/upb.c
+++ b/upb/bindings/lua/upb.c
@@ -53,7 +53,7 @@ static size_t lupb_msgdef_sizeof();
  * compatibility code can help hide the difference.  Not too many people still
  * use Lua 5.1 but LuaJIT uses the Lua 5.1 API in some ways. */
 
-#if lua_version_num == 501
+#if LUA_VERSION_NUM == 501
 
 /* taken from lua 5.2's source. */
 void *luaL_testudata(lua_State *L, int ud, const char *tname) {
diff --git a/upb/bindings/lua/upb.lua b/upb/bindings/lua/upb.lua
index 4090b37a6f..8b32cff664 100644
--- a/upb/bindings/lua/upb.lua
+++ b/upb/bindings/lua/upb.lua
@@ -14,7 +14,10 @@
 -- This has to happen *before* the require call, because if the module
 -- is loaded RTLD_LOCAL first, a subsequent load as RTLD_GLOBAL won't
 -- have the proper effect, at least on some platforms.
-package.loadlib(package.searchpath("upb_c", package.cpath), "*")
+local so = package.searchpath and package.searchpath("upb_c", package.cpath)
+if so then
+  package.loadlib(so, "*")
+end
 
 local upb = require("upb_c")
 
diff --git a/upb/pb/textprinter.c b/upb/pb/textprinter.c
index b772af33f4..269881b91b 100644
--- a/upb/pb/textprinter.c
+++ b/upb/pb/textprinter.c
@@ -112,7 +112,7 @@ bool putf(upb_textprinter *p, const char *fmt, ...) {
 
   /* Run once to get the length of the string. */
   va_copy(args_copy, args);
-  len = vsprintf(NULL, fmt, args_copy);
+  len = _upb_vsnprintf(NULL, 0, fmt, args_copy);
   va_end(args_copy);
 
   /* + 1 for NULL terminator (vsprintf() requires it even if we don't). */
diff --git a/upb/table.c b/upb/table.c
index cee2cf82e9..943290e0c6 100644
--- a/upb/table.c
+++ b/upb/table.c
@@ -439,14 +439,16 @@ size_t upb_inttable_count(const upb_inttable *t) {
 static void check(upb_inttable *t) {
   UPB_UNUSED(t);
 #if defined(UPB_DEBUG_TABLE) && !defined(NDEBUG)
-  /* This check is very expensive (makes inserts/deletes O(N)). */
-  size_t count = 0;
-  upb_inttable_iter i;
-  upb_inttable_begin(&i, t);
-  for(; !upb_inttable_done(&i); upb_inttable_next(&i), count++) {
-    assert(upb_inttable_lookup(t, upb_inttable_iter_key(&i), NULL));
+  {
+    /* This check is very expensive (makes inserts/deletes O(N)). */
+    size_t count = 0;
+    upb_inttable_iter i;
+    upb_inttable_begin(&i, t);
+    for(; !upb_inttable_done(&i); upb_inttable_next(&i), count++) {
+      assert(upb_inttable_lookup(t, upb_inttable_iter_key(&i), NULL));
+    }
+    assert(count == upb_inttable_count(t));
   }
-  assert(count == upb_inttable_count(t));
 #endif
 }