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

CMakeLists.txt

@@ -44,7 +44,7 @@ set_source_files_properties(
 # versions in a synchronised way.
 set(PROJECT_VERSION_MAJOR "0")
 set(PROJECT_VERSION_MINOR "2")
-set(PROJECT_VERSION_PATCH "18")
+set(PROJECT_VERSION_PATCH "19")
 set(PROJECT_VERSION "${PROJECT_VERSION_MAJOR}.${PROJECT_VERSION_MINOR}.${PROJECT_VERSION_PATCH}")
 
 # set .so library version / following libtool scheme
@@ -146,6 +146,8 @@ endif()
 option(BUILD_MISC_TESTS "Build additional tests" OFF)
 option(BUILD_FUN_UTILS "Build additional just for fun utilities" OFF)
 
+option(UNITTEST "Enable unit tests (disable if you don't have a working gmock or gtest)" ON)
+
 option(AUTOTEST "Enable autotests (mainly for CI)" OFF)
 if(AUTOTEST)
   option(NON_HERMETIC_TESTS "Whether to build and run tests that depend on an internet connection" OFF)
@@ -534,7 +536,7 @@ endfunction()
 
 # The actual unit tests follow.
 #
-if(TARGET GTest::gtest AND TARGET GTest::gmock)
+if(UNITTEST AND TARGET GTest::gtest AND TARGET GTest::gmock)
   unit_test(toxav ring_buffer)
   unit_test(toxav rtp)
   unit_test(toxcore DHT)