cmake GIO examples

TigerVNC/tigervnc CMakeLists.txt :398 

find_package(Gio)

TheImagingSource/tiscamera src/aravis/CMakeLists.txt :50 

find_package(GIO     REQUIRED QUIET)

JoseExposito/touchegg CMakeLists.txt :28 

find_package(GIO REQUIRED)