LIBLWIP - fixed clang warnings

lib/liblwip/include/arch/cc.h

@@ -4,6 +4,7 @@
 #include <sys/cdefs.h>
 #include <sys/time.h>
 #include <sys/types.h>
+#include <minix/sysutil.h>
 #include <errno.h>
 #include <assert.h>
 

lib/liblwip/include/lwip/mem.h

@@ -41,6 +41,7 @@ extern "C" {
 #if MEM_LIBC_MALLOC
 
 #include <stddef.h> /* for size_t */
+#include <stdlib.h>
 
 typedef size_t mem_size_t;
 

lib/liblwip/include/lwipopts.h

@@ -68,7 +68,7 @@
 #define CHECKSUM_CHECK_TCP              	1
 
 #define TCP_MSS				(1460)
-#define TCP_SND_BUF			(256 * TCP_MSS)
+#define TCP_SND_BUF			(44 * TCP_MSS)
 #define TCP_SNDLOWAT			(256)
 #define TCP_SND_QUEUELEN		(512)
 #define TCP_WND				((1 << 16) - 1)