AC_CACHE_CHECK([INET6_ADDRSTRLEN],[ol_cv_inet6_addrstrlen],[
AC_EGREP_CPP(__has_inet6_addrstrlen__,[
# include <netinet/in.h>
AC_CACHE_CHECK([INET6_ADDRSTRLEN],[ol_cv_inet6_addrstrlen],[
AC_EGREP_CPP(__has_inet6_addrstrlen__,[
# include <netinet/in.h>