cmake libsystemd examples

Tinob/Ishiiruka CMakeLists.txt :750 

find_package(Libsystemd)

FreeRDP/FreeRDP winpr/libwinpr/utils/CMakeLists.txt :97 

find_package(libsystemd)

getdnsapi/stubby CMakeLists.txt :46 

find_package(Libsystemd)