libdir can be something else than /usr/lib, e.g. /usr/lib64 or similar.
@@ -119,11 +119,11 @@ configure_file(config.cmake.in 
 install(FILES
        "${PROJECT_BINARY_DIR}/cmake/${PROJECT_NAME}Config.cmake"
        "${PROJECT_BINARY_DIR}/cmake/${PROJECT_NAME}ConfigVersion.cmake"
-       DESTINATION "lib/cmake/${PROJECT_NAME}")
+       DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/${PROJECT_NAME}")
 install(
        EXPORT ${LIBGIT2_TARGETS_EXPORT_NAME}
        NAMESPACE "${PROJECT_NAME}::"
-       DESTINATION "lib/cmake/${PROJECT_NAME}")
+       DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/${PROJECT_NAME}")
 
 # Install