Add support for C11 stdatomic atomics

This fixes deprecation warnings when building for macOS >= 10.12 systems.
Additionally, using stdatomic.h (or the more modern __atomic_ builtins)
is required when targeting CHERI-enabled architectures such as
CHERI-RISC-V or Arm's Morello since the compiler rejects __sync_* atomic
for pointer types (they only work with integers).

1 files changed, 8 insertions, 0 deletions

diff --git a/meson-cc-tests/stdatomic-primitives-test.c b/meson-cc-tests/stdatomic-primitives-test.c
new file mode 100644
index 0000000..6d11d34
--- /dev/null
+++ b/meson-cc-tests/stdatomic-primitives-test.c
@@ -0,0 +1,8 @@
+#include <stdatomic.h>
+
+void memory_barrier (void) { atomic_thread_fence (memory_order_acq_rel); }
+int atomic_add (atomic_int *i) { return atomic_fetch_add_explicit (i, 1, memory_order_relaxed); }
+int mutex_trylock (atomic_flag *m) { return atomic_flag_test_and_set_explicit (m, memory_order_acquire); }
+void mutex_unlock (atomic_flag *m) { atomic_flag_clear_explicit (m, memory_order_release); }
+
+int main(void) { return 0;}