Add priority argument to thread sys_thread_new.Patch from floriZ but slightly modfied

src/include/lwip/opt.h

@@ -296,6 +296,18 @@ a lot of data that needs to be copied, this should be set high. */
 #define LWIP_COMPAT_SOCKETS     1
 #endif
 
+
+#ifndef TCPIP_THREAD_PRIO
+#define TCPIP_THREAD_PRIO 1
+#endif
+
+#ifndef SLIPIF_THREAD_PRIO
+#define SLIPIF_THREAD_PRIO 1
+#endif
+
+#ifndef DEFAULT_THREAD_PRIO
+#define DEFAULT_THREAD_PRIO 1
+#endif
 /* ---------- Statistics options ---------- */
 #ifndef LWIP_STATS
 #define LWIP_STATS	1

src/include/lwip/sys.h

@@ -57,7 +57,7 @@ struct sys_timeout {u8_t dummy;};
 #define sys_mbox_post(m,d)
 #define sys_mbox_free(m)
 
-#define sys_thread_new(t,a)
+#define sys_thread_new(t,a,p)
 
 /* We don't need protection if there is no OS */
 #define SYS_ARCH_DECL_PROTECT(lev)
@@ -157,7 +157,7 @@ void sys_arch_unprotect(sys_prot_t pval);
 #endif /* SYS_ARCH_PROTECT */
 
 /* Thread functions. */
-sys_thread_t sys_thread_new(void (* thread)(void *arg), void *arg);
+sys_thread_t sys_thread_new(void (* thread)(void *arg), void *arg, int prio);
 
 /* The following functions are used only in Unix code, and
    can be omitted when porting the stack. */