CMake: Use PROJECT_SOURCE_DIR
CMake: Use PROJECT_SOURCE_DIR

LebedevRI/rawspeed,anarsoul/rawspeed,darktable-org/rawspeed,darktable-org/rawspeed,LebedevRI/rawspeed,anarsoul/rawspeed,LebedevRI/rawspeed,darktable-org/rawspeed,LebedevRI/rawspeed,anarsoul/rawspeed,darktable-org/rawspeed,darktable-org/rawspeed,LebedevRI/rawspeed