Use the crypto random functions instead of `rand()`.

Presumably the uses of `rand()` were fine because they were not used in
security-sensitive places, but having to think about whether a crappy RNG
is acceptable in each situation requires effort that could better be
spent elsewhere.

Also, this means that once we have a custom deterministic RNG for
testing, that RNG is used everywhere, so all the code is deterministic.

It also allowed us to delete a system-specific function that wasn't used
anywhere except in a call to `srand()`.

1 files changed, 2 insertions, 2 deletions

diff --git a/toxcore/group.c b/toxcore/group.c
index 317b885f..f62684ed 100644
--- a/toxcore/group.c
+++ b/toxcore/group.c
@@ -1490,12 +1490,12 @@ static void handle_friend_invite_packet(Messenger *m, uint32_t friendnumber, con
 
             /* TODO(irungentoo): what if two people enter the group at the same time and
                are given the same peer_number by different nodes? */
-            uint16_t peer_number = rand();
+            uint16_t peer_number = random_u16();
 
             unsigned int tries = 0;
 
             while (get_peer_index(g, peer_number) != -1) {
-                peer_number = rand();
+                peer_number = random_u16();
                 ++tries;
 
                 if (tries > 32) {