[Boost-users] [asio] __sync_lock_test_and_set problem, cross-compiling for ARM

Hello, I'm trying to cross-compile my project for Android (Win, cygwin, crystax-ndk). The linker emits the following error: ../asio/detail/gcc_fenced_block.hpp:41: undefined reference to `__sync_lock_test_and_set_4' I understand that in 1.44 I can disable this "fenced-block" by defining BOOST_ASIO_DISABLE_FENCED_BLOCK, but I'm not sure it's safe to do this. IUUC, __sync_lock_test_and_set gcc function is unavailable for some older arm-based platforms, but should be available for the newer ones, shouldn't it? So maybe I have to define some compiler flag to enable it? I'd appreciate any idea. Thanks.