Fix incorrect libxml fprintf, erroring on clang win x64

third_party/libxml/src/timsort.h

Index: third_party/libxml/src/timsort.h
diff --git a/third_party/libxml/src/timsort.h b/third_party/libxml/src/timsort.h
index efa3aab142d10b2117733c42e4b96d48c82a1081..43cb1fa24b542b8746aed7c3ca35187c7c0367a8 100644
--- a/third_party/libxml/src/timsort.h
+++ b/third_party/libxml/src/timsort.h
@@ -27,6 +27,9 @@ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLI
 #elif defined(WIN32)
 typedef __int64 int64_t;
 typedef unsigned __int64 uint64_t;
+#if !defined(PRIuS)
+#define PRIuS "Iu"
+#endif
 #endif
 #endif
 
@@ -323,7 +326,7 @@ static void TIM_SORT_RESIZE(TEMP_STORAGE_T *store, const size_t new_size)
     SORT_TYPE *tempstore = (SORT_TYPE *)realloc(store->storage, new_size * sizeof(SORT_TYPE));
     if (tempstore == NULL)
     {
-      fprintf(stderr, "Error allocating temporary storage for tim sort: need %lu bytes", sizeof(SORT_TYPE) * new_size);
+      fprintf(stderr, "Error allocating temporary storage for tim sort: need %" PRIuS " bytes", sizeof(SORT_TYPE) * new_size);
       exit(1);
     }
     store->storage = tempstore;