The latest version of this document lives in the vcpkg repo.
Modify a host path list variable (PATH, INCLUDE, LIBPATH, etc.)
vcpkg_host_path_list(PREPEND <list-var> [<path>...]) vcpkg_host_path_list(APPEND <list-var> [<path>...]) vcpkg_host_path_list(SET <list-var> [<path>...])
<list-var> may be either a regular variable name, or
in which case
vcpkg_host_path_list will modify the environment.
vcpkg_host_path_list adds all of the paths passed to it to
PREPEND puts them before the existing list, so that they are searched first;
APPEND places them after the existing list,
so they would be searched after the paths which are already in the variable,
SET replaces the value of the existing list.
For all of
the paths are added (and thus searched) in the order received.
If no paths are passed to
PREPEND, nothing will be done;
SET, the variable will be set to the empty string.