Squashed 'external/toxcore/c-toxcore/' changes from adbd5b32d8..e29e185c03

e29e185c03 feat: add ngc events
2b0dc0f46b add ngc related unpack functions
b2315c50e0 Add groupchat API function that returns an IP address string for a peer
5f863a5492 feat: Add `to_string` functions for all public enums.
0c998a7598 add real timeout test
68c827609a chore: Move s390x build to post-merge.
028b017d79 perf: Slightly reduce bandwidth usage when there are few nodes.
90f7496819 feat: Enable ubsan on bootstrap nodes.
89b6450d66 test: Add check-c run to bazel build.
REVERT: adbd5b32d8 feat: add ngc events

git-subtree-dir: external/toxcore/c-toxcore
git-subtree-split: e29e185c03fea7337036e5ef4d1d9080a6cee721

toxcore/network.h

@@ -343,11 +343,14 @@ bool ipv6_ipv4_in_v6(const IP6 *a);
 /** this would be TOX_INET6_ADDRSTRLEN, but it might be too short for the error message */
 #define IP_NTOA_LEN 96 // TODO(irungentoo): magic number. Why not INET6_ADDRSTRLEN ?
 
+/** Contains a null terminated string of an IP address. */
 typedef struct Ip_Ntoa {
-    char buf[IP_NTOA_LEN];
+    char     buf[IP_NTOA_LEN];  // a string formatted IP address or an error message.
+    uint16_t length;  // the length of the string (not including the null byte).
+    bool     ip_is_valid;  // if this is false `buf` will contain an error message.
 } Ip_Ntoa;
 
-/** @brief Converts IP into a string.
+/** @brief Converts IP into a null terminated string.
  *
  * Writes error message into the buffer on error.
  *