cmake STDLIBS_HAVE_GETHOSTBYADDR examples

CTSRD-CHERI/cheribsd contrib/tcpdump/CMakeLists.txt :454 

check_function_exists(gethostbyaddr STDLIBS_HAVE_GETHOSTBYADDR)

CTSRD-CHERI/cheribsd contrib/tcpdump/CMakeLists.txt :472 

endif(NOT STDLIBS_HAVE_GETHOSTBYADDR)