Update pingcheck to work with cmake 3.28

[pingcheck] / doc / doxyfile.in

INPUT = @CMAKE_CURRENT_SOURCE_DIR@/config/ @CMAKE_CURRENT_SOURCE_DIR@/config/option @CMAKE_CURRENT_SOURCE_DIR@/dns/ @CMAKE_CURRENT_SOURCE_DIR@/host/ @CMAKE_CURRENT_SOURCE_DIR@/icmp/ @CMAKE_CURRENT_SOURCE_DIR@/ip/ @CMAKE_CURRENT_SOURCE_DIR@/link/ @CMAKE_CURRENT_SOURCE_DIR@/tcp/