Running on Ubuntu 18.04, cmake version 3.18.0-rc2. From documentation I expect CMAKE_SYSTEM_INCLUDE_PATH to hold a list of directories including /usr/include, /usr/local/include, etc. :
Semicolon-separated list of directories specifying a search path for the find_file() and find_path() commands. By default this contains the standard directories for the current system.
However when I print the value of CMAKE_SYSTEM_INCLUDE_PATH from my CMakeLists.txt I get:
CMAKE_SYSTEM_INCLUDE_PATH: /usr/include/X11
Why is this? Thanks!