Merge "Disable availability macros in libc++ on Darwin."

ifneq ($(filter $(my_cxx_stl),libc++ libc++_static),)

    my_cflags += -D_USING_LIBCXX

    ifeq ($($(my_prefix)OS),darwin)

        # libc++'s headers are annotated with availability macros that indicate

        # which version of Mac OS was the first to ship with a libc++ feature

        # available in its *system's* libc++.dylib. We do not use the system's

        # library, but rather ship our own. As such, these availability

        # attributes are meaningless for us but cause build breaks when we try

        # to use code that would not be available in the system's dylib.

        my_cppflags += -D_LIBCPP_DISABLE_AVAILABILITY

    endif

    # Note that the structure of this means that LOCAL_CXX_STL := libc++ will

    # use the static libc++ for static executables.

    ifeq ($(my_link_type),dynamic)