Explicitly link against libatomic on Linux arm (#7257)

* Explicitly link against libatomic on Linux arm

* changelog

CHANGELOG.md

@@ -7,6 +7,7 @@
 ### Fixed
 * Handle `EOPNOTSUPP` when using `posix_fallocate()` and fallback to manually consume space. This should enable android users to open a Realm on restrictive filesystems. ([realm-js #6349](https://github.com/realm/realm-js/issues/6349), more prevalent since v13.23.3 with the change to `REALM_HAVE_POSIX_FALLOCATE` but it was also an issue in some platforms before this)
 * Application may crash with `incoming_changesets.size() != 0` when a download message is mistaken for a bootstrap message (PR [#7238](https://github.com/realm/realm-core/pull/7238), since v11.8.0)
+* Fixed errors complaining about missing symbols such as `__atomic_is_lock_free` on ARMv7 Linux. (PR [#7257](https://github.com/realm/realm-core/pull/7257))
 
 ### Breaking changes
 * `App::get_uncached_app(...)` and `App::get_shared_app(...)` have been replaced by `App::get_app(App::CacheMode, ...)`. The App constructor is now enforced to be unusable, use `App::get_app()` instead. ([#7237](https://github.com/realm/realm-core/issues/7237))

src/realm/CMakeLists.txt

@@ -363,6 +363,10 @@ elseif(ANDROID)
     target_link_options(Storage INTERFACE LINKER:-gc-sections)
 elseif(APPLE)
     target_link_options(Storage INTERFACE "SHELL:-framework Foundation")
+elseif(LINUX)
+    if(CMAKE_SYSTEM_PROCESSOR MATCHES "^armv7")
+        target_link_libraries(Storage INTERFACE atomic)
+    endif()
 endif()
 
 target_link_libraries(Storage INTERFACE Threads::Threads)