Add tox_wait() for socket, allow tox.h include in tox.c

tox.*, Messenger.*, network.*;
- new function tox_wait() => waitMessenger() => networking_wait():
  - waits for a given amount of time for any sort of socket activity
  - mustn't change anything inside, mustn't poll or do other stuff
    - the point is to be able to call this asynchronously from a second thread
    - the outside shall follow up with an immediate tox_do() when there's socket activity

tox.*:
- allow inclusion of tox.h into tox.c, ensuring that the outside interface and the internal always match

util.c:
- squished a few warnings about questionable format strings

1 files changed, 16 insertions, 0 deletions

diff --git a/toxcore/Messenger.c b/toxcore/Messenger.c
index c8d69494..54ee6cce 100644
--- a/toxcore/Messenger.c
+++ b/toxcore/Messenger.c
@@ -26,6 +26,7 @@
 #endif
 
 #include "Messenger.h"
+#include "network.h"
 #include "util.h"
 
 #define MIN(a,b) (((a)<(b))?(a):(b))
@@ -1388,6 +1389,21 @@ void doMessenger(Messenger *m)
 #endif
 }
 
+/*
+ * Waits for something to happen on the socket for up to milliseconds milliseconds
+ * *** Function MUSTN'T poll. ***
+ * The function mustn't modify anything at all, so it can be called completely
+ * asynchronously without any worry.
+ *
+ *  returns 0 if the timeout was reached
+ *  returns 1 if there is socket activity (i.e. tox_do() should be called)
+ *
+ */
+int waitMessenger(Messenger *m, uint16_t milliseconds)
+{
+    return networking_wait(m->net, milliseconds);
+};
+
 /*  return size of the messenger data (for saving) */
 uint32_t Messenger_size_old(Messenger *m)
 {