Build instruction:

mkdir build
cd build
cmake ..
cmake --build . --target install

You can use this library in your project like this

cmake_minimum_required(VERSION 3.0)
project(gherkincsample)
list(APPEND CMAKE_PREFIX_PATH "INSTALLATION_DIRECTORY")
set(CMAKE_CXX_STANDARD 11)
find_package(gherkin REQUIRED)
add_executable(gherkincsample main.cpp)
target_link_libraries(gherkincsample gherkin::gherkin)

The docs are here.