gentoo-overlay/dev-libs/protobuf/files/protobuf-3.5.0-atomic_operations.patch

https://github.com/protocolbuffers/protobuf/issues/3937
https://github.com/protocolbuffers/protobuf/pull/3955
https://github.com/protocolbuffers/protobuf/commit/642e1ac635f2563b4a14c255374f02645ae85dac

--- /src/google/protobuf/stubs/atomicops_internals_generic_gcc.h
+++ /src/google/protobuf/stubs/atomicops_internals_generic_gcc.h
@@ -146,6 +146,14 @@
   return __atomic_load_n(ptr, __ATOMIC_RELAXED);
 }
 
+inline Atomic64 Release_CompareAndSwap(volatile Atomic64* ptr,
+                                       Atomic64 old_value,
+                                       Atomic64 new_value) {
+  __atomic_compare_exchange_n(ptr, &old_value, new_value, false,
+                              __ATOMIC_RELEASE, __ATOMIC_ACQUIRE);
+  return old_value;
+}
+
 #endif // defined(__LP64__)
 
 }  // namespace internal