Merge branch 'features/lwip-SO_REUSEADDR' into 'master'

Enable SO_REUSEADDR in LWIP

Daniel initially asked me why this wasn't enabled, and I don't think I got any reasons against enabling this. If any, it makes porting existing software easier. Tuan needs it for UDP multicast as well.

Code changes are by Tuan: basically the enable for SO_REUSEADDR in LWIP as well as a bugfix in a bit of mbedTLS that gets enabled.

See merge request !90

components/lwip/include/lwip/port/lwipopts.h

@@ -405,7 +405,7 @@ extern unsigned char misc_prof_get_tcp_snd_buf(void);
 /**
  * SO_REUSE==1: Enable SO_REUSEADDR option.
  */
-#define SO_REUSE                        0
+#define SO_REUSE                        1
 
 /*
    ----------------------------------------

components/mbedtls/port/net.c

@@ -147,7 +147,7 @@ int mbedtls_net_bind( mbedtls_net_context *ctx, const char *bind_ip, const char
 
         /*SO_REUSEADDR option dafault is disable in source code(lwip)*/
 #if SO_REUSE
-        n = 1;
+        int n = 1;
         if ( setsockopt( ctx->fd, SOL_SOCKET, SO_REUSEADDR,
                          (const char *) &n, sizeof( n ) ) != 0 ) {
             close( ctx->fd );