geos provides CMake targets:

  # C API (provides long-term ABI stability)
  find_package(GEOS CONFIG REQUIRED)
  target_link_libraries(main PRIVATE GEOS::geos_c)

  # C++ API (will likely change across versions)
  find_package(GEOS CONFIG REQUIRED)
  target_link_libraries(main PRIVATE GEOS::geos)

geos provides pkg-config modules:

  # Geometry Engine, Open Source - C API
  geos