Fix running IPv6 reassembly unit tests on 64-bit

test/unit/lwipopts.h

@@ -59,7 +59,7 @@
 #define LWIP_DNS_SECURE (LWIP_DNS_SECURE_RAND_XID | LWIP_DNS_SECURE_RAND_SRC_PORT)
 
 /* Minimal changes to opt.h required for tcp unit tests: */
-#define MEM_SIZE                        16000
+#define MEM_SIZE                        17000
 #define TCP_SND_QUEUELEN                40
 #define MEMP_NUM_TCP_SEG                TCP_SND_QUEUELEN
 #define TCP_SND_BUF                     (12 * TCP_MSS)
@@ -91,4 +91,27 @@
 /* Check lwip_stats.mem.illegal instead of asserting */
 #define LWIP_MEM_ILLEGAL_FREE(msg)      /* to nothing */
 
+/* autodetect if we are running the tests on 32-bit or 64-bit */
+#if defined(_WIN32) || defined(_WIN64)
+#if defined(_WIN64)
+#define PTR64
+#else
+#define PTR32
+#endif
+#elif defined(__GNUC__)
+#if defined(__x86_64__) || defined(__ppc64__)
+#define PTR64
+#else
+#define PTR32
+#endif
+#elif UINTPTR_MAX > UINT_MAX
+#define PTR64
+#else
+#define PTR32
+#endif
+
+#ifdef PTR64
+#define IPV6_FRAG_COPYHEADER            1
+#endif
+
 #endif /* LWIP_HDR_LWIPOPTS_H */