Squashed 'external/toxcore/c-toxcore/' changes from 3e05824b80..da438763d5

da438763d5 chore: Release 0.2.19
f90417987c chore: Add cmake flag to disable unit tests.
7df3f99417 docs: Document that group topic lock is default on.
9e9ed77390 docs: Add missing param docs for callbacks.
0ec4978de5 refactor: Don't expose Tox_System in the public API
a3d1b8595c docs: Public headers, Core/toxcore -> Tox/the Tox library
f78d0f3f39 docs: Public headers, events_alloc -> internal
817518949e docs: Public headers, NULL-terminated -> NUL-terminated
be085db191 docs: Public headers, spellcheck
4c902955f3 docs: Public headers, 80 column width comments
be8a82a818 docs: Public headers, null -> NULL
419d783d95 docs: Public headers, tox -> Tox
5c8aa65e41 docs: Update user data API explanation
ad4921dbaa cleanup: A more descriptive error for group invite accept function

git-subtree-dir: external/toxcore/c-toxcore
git-subtree-split: da438763d5b8e071de6e061a1dcaddd2177dff7d

toxcore/tox_events.h

@@ -2,6 +2,13 @@
  * Copyright © 2022-2024 The TokTok team.
  */
 
+/**
+ * WARNING: This is an experimental API and is subject to change.
+ *
+ * At this point, it probably won't change very much anymore, but we may have
+ * small breaking changes before a stable release.
+ */
+
 #ifndef C_TOXCORE_TOXCORE_TOX_EVENTS_H
 #define C_TOXCORE_TOXCORE_TOX_EVENTS_H
 
@@ -570,6 +577,8 @@ void tox_events_free(Tox_Events *events);
 uint32_t tox_events_bytes_size(const Tox_Events *events);
 bool tox_events_get_bytes(const Tox_Events *events, uint8_t *bytes);
 
+typedef struct Tox_System Tox_System;
+
 Tox_Events *tox_events_load(const Tox_System *sys, const uint8_t *bytes, uint32_t bytes_size);
 
 bool tox_events_equal(const Tox_System *sys, const Tox_Events *a, const Tox_Events *b);