To enable the overlay, place it somewhere in the project tree and add the root of the overlay's relative path to your vcpkg-configuration.json's overlay-ports section, or in case no vcpkg-configuration.json exists, create it using
{
"$schema": "https://raw.githubusercontent.com/microsoft/vcpkg-tool/main/docs/vcpkg-configuration.schema.json",
"overlay-ports": ["./path-to-tkrzw-vcpkg-overlay"]
}
, replacing ./path-to-tkrzw-vcpkg-overlay with the overlay's path in relation to the project's top level.