std::once_flag was forward declared with _LIBCPP_TYPE_VIS decoration, and the defined with _LIBCPP_TYPE_VIS_ONLY decoration. Make them match git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@214219 91177308-0d34-0410-b5e6-96231b3b80d8 
diff --git a/include/mutex b/include/mutex index e0c02ad..5dfba63 100644 --- a/include/mutex +++ b/include/mutex 
@@ -425,7 +425,7 @@    #endif // _LIBCPP_HAS_NO_VARIADICS   -struct _LIBCPP_TYPE_VIS once_flag; +struct _LIBCPP_TYPE_VIS_ONLY once_flag;    #ifndef _LIBCPP_HAS_NO_VARIADICS