Transitively require other imported library's interface from imported library - cmake

Question

CMake 3.5
I have an existing external library, which I have made an IMPORTED library in my CMakeLists.txt:
find_path(
FOO_INCLUDE_DIR NAMES foo.h
PATHS "${FOO_ROOT}"
NO_DEFAULT_PATH
PATH_SUFFIXES include/foo
)
find_library(
FOO_LIBRARY NAMES foo
PATHS "${FOO_ROOT}"
PATH_SUFFIXES lib
)
mark_as_advanced(FOO_INCLUDE_DIR FOO_LIBRARY)
find_package_handle_standard_args(
FOO REQUIRED_VARS
FOO_INCLUDE_DIR
FOO_LIBRARY
)
add_library(Foo::Foo SHARED IMPORTED)
set_property(TARGET Foo::Foo
PROPERTY INTERFACE_INCLUDE_DIRECTORIES
"${FOO_INCLUDE_DIR}" "${BAR_INCLUDE_DIR}"
"${Boost_INCLUDE_DIRS}" "${BAZ_INCLUDE_DIR}"
)
set_property(TARGET Foo::Foo
PROPERTY IMPORTED_LOCATION
"${FOO_LIBRARY}"
)
set_property(TARGET Foo::Foo
PROPERTY INTERFACE_LINK_LIBRARIES
"${Boost_LIBRARIES}" "${BAR_LIBRARY}" "${BAZ_LIBRARIES}"
)
Programs that link with this particular library need thread support. Adding thread support to something is fairly straightforward:
set(THREADS_PREFER_PTHREAD_FLAG on)
include(FindThreads)
...
target_link_libraries(something PUBLIC Threads::Threads)
I would like anything that links against Foo::Foo to automatically include Threads::Threads. But you can't use target_link_libraries() on an IMPORTED library. So how do I transitively require Threads::Threads from Foo::Foo?
I managed to work around this by doing the following, but it depended on me checking to see what properties FindThreads sets on Threads::Threads. Is there a better way?
set_property(TARGET Foo::Foo
PROPERTY INTERFACE_LINK_LIBRARIES
"${Boost_LIBRARIES}" "${BAR_LIBRARY}" "${BAZ_LIBRARIES}"
$<TARGET_PROPERTY:Threads::Threads,INTERFACE_LINK_LIBRARIES>
)
set_property(TARGET Foo::Foo
PROPERTY INTERFACE_COMPILE_OPTIONS
$<TARGET_PROPERTY:Threads::Threads,INTERFACE_COMPILE_OPTIONS>
)

Answer 1

It turns out the answer was quite simple. I simple needed to add Threads::Threads to the INTERFACE_LINK_LIBRARIES property of Foo::Foo. I have no idea why I had determined that would not work the first time around.