cmake poly2tri examples

keith2018/SoftGLRender third_party/assimp/code/CMakeLists.txt :936 

find_package(poly2tri CONFIG REQUIRED)

google/filament third_party/libassimp/code/CMakeLists.txt :895 

find_package(poly2tri CONFIG REQUIRED)

meemknight/ourCraft thirdparty/assimp-5.2.4/code/CMakeLists.txt :935 

find_package(poly2tri CONFIG REQUIRED)