Obey device "md" (metadata) tag - credit @couteau

- original patch https://gist.github.com/couteau/7532531

src/player.c

@@ -3716,6 +3716,7 @@ raop_device_cb(const char *name, const char *type, const char *domain, const cha
   char *at_name;
   char *password;
   uint64_t id;
+  char wants_metadata;
   char has_password;
   enum raop_devtype devtype;
   int ret;
@@ -3850,6 +3851,25 @@ raop_device_cb(const char *name, const char *type, const char *domain, const cha
     devtype = OTHER;
 
  no_am:
+  wants_metadata = 0;
+  p = keyval_get(txt, "md");
+  if (!p)
+    {
+      DPRINTF(E_LOG, L_PLAYER, "AirTunes %s: no md field in TXT record!\n", name);
+
+      goto no_md;
+    }
+
+  if (*p == '\0')
+    {
+      DPRINTF(E_LOG, L_PLAYER, "AirTunes %s: md has no value\n", name);
+
+      goto no_md;
+    }
+
+  wants_metadata = 1;
+
+ no_md:
   DPRINTF(E_DBG, L_PLAYER, "AirTunes device %s: password: %s, type %s\n", name, (password) ? "yes" : "no", raop_devtype[devtype]);
 
   rd->advertised = 1;
@@ -3869,6 +3889,7 @@ raop_device_cb(const char *name, const char *type, const char *domain, const cha
 
   rd->devtype = devtype;
 
+  rd->wants_metadata = wants_metadata;
   rd->has_password = has_password;
   rd->password = password;
 

src/raop.c

@@ -1848,31 +1848,28 @@ raop_session_make(struct raop_device *rd, int family, raop_status_cb cb)
   rs->server_fd = -1;
 
   rs->password = rd->password;
+  rs->wants_metadata = rd->wants_metadata;
 
   switch (rd->devtype)
     {
       case RAOP_DEV_APEX_80211G:
 	rs->encrypt = 1;
 	rs->auth_quirk_itunes = 1;
-	rs->wants_metadata = 0;
 	break;
 
       case RAOP_DEV_APEX_80211N:
 	rs->encrypt = 1;
 	rs->auth_quirk_itunes = 0;
-	rs->wants_metadata = 0;
 	break;
 
       case RAOP_DEV_APPLETV:
 	rs->encrypt = 0;
 	rs->auth_quirk_itunes = 0;
-	rs->wants_metadata = 1;
 	break;
 
       case OTHER:
 	rs->encrypt = 0;
 	rs->auth_quirk_itunes = 0;
-	rs->wants_metadata = 0;
 	break;
     }
 

src/raop.h

@@ -40,6 +40,7 @@ struct raop_device
   unsigned selected:1;
   unsigned advertised:1;
 
+  unsigned wants_metadata:1;
   unsigned has_password:1;
   const char *password;