headeronly_library

https://cmake.org/cmake/help/latest/command/add_library.html#interface-libraries

header only のライブラリで、dll や so への link が発生しない場合に使う。

# Catch2 header only
add_library(catch INTERFACE)
target_include_directories(catch INTERFACE ${CMAKE_CURRENT_LIST_DIR})
target_compile_options(catch INTERFACE /wd4996)

# ASIO header only
add_library(asio INTERFACE)
target_include_directories(asio INTERFACE asio/asio/include)