diff --git a/src/include/lwip/arch.h b/src/include/lwip/arch.h
index 18228c56..50337022 100644
--- a/src/include/lwip/arch.h
+++ b/src/include/lwip/arch.h
@@ -116,12 +116,20 @@
 /* Define generic types used in lwIP */
 #if !LWIP_NO_STDINT_H
 #include <stdint.h>
+/* stdint.h is C99 which should also provide support for 64-bit integers */
+#if !defined(LWIP_HAVE_INT64) && defined(UINT64_MAX)
+#define LWIP_HAVE_INT64 1
+#endif
 typedef uint8_t   u8_t;
 typedef int8_t    s8_t;
 typedef uint16_t  u16_t;
 typedef int16_t   s16_t;
 typedef uint32_t  u32_t;
 typedef int32_t   s32_t;
+#if LWIP_HAVE_INT64
+typedef uint64_t  u64_t;
+typedef int64_t   s64_t;
+#endif
 typedef uintptr_t mem_ptr_t;
 #endif