diff --git a/BUILD b/BUILD
new file mode 100644
index 0000000..11d2ad0
--- /dev/null
+++ b/BUILD
@@ -0,0 +1,12 @@
+# -*- mode: gn -*-
+package(default_visibility = ["//visibility:public"])
+
+cc_library(
+    name = "frozen",
+    srcs = [
+        "frozen.c",
+    ],
+    hdrs = [
+        "frozen.h",
+    ],
+)
diff --git a/frozen.c b/frozen.c
index b614128..4b5e279 100644
--- a/frozen.c
+++ b/frozen.c
@@ -47,18 +47,22 @@ typedef unsigned _int64 uint64_t;
 #endif
 #define PRId64 "I64d"
 #define PRIu64 "I64u"
+#if !defined(SIZE_T_FMT)
 #if _MSC_VER >= 1310
 #define SIZE_T_FMT "Iu"
 #else
 #define SIZE_T_FMT "u"
 #endif
+#endif
 #else /* _WIN32 */
 /* <inttypes.h> wants this for C++ */
 #ifndef __STDC_FORMAT_MACROS
 #define __STDC_FORMAT_MACROS
 #endif
 #include <inttypes.h>
+#if !defined(SIZE_T_FMT)
 #define SIZE_T_FMT "zu"
+#endif
 #endif /* _WIN32 */
 
 #define INT64_FMT PRId64