+dnl ----------------------------------------------------------------
+dnl PF_INET6 support requires getaddrinfo and INET6_ADDRSTRLEN
+dnl PF_LOCAL may use getaddrinfo in available
+AC_CHECK_FUNCS( getaddrinfo inet_ntop )
+
+ol_link_ipv6=no
+if test $ac_cv_func_getaddrinfo = no -o $ac_cv_func_inet_ntop = no ; then
+ if test $ol_enable_ipv6 = yes ; then
+ AC_MSG_ERROR([IPv6 support requires getaddrinfo() and inet_ntop()])
+ fi
+else
+ AC_CHECK_FUNCS( gai_strerror )
+
+ AC_CACHE_CHECK([INET6_ADDRSTRLEN],[ol_cv_inet6_addrstrlen],[
+ AC_EGREP_CPP(__has_inet6_addrstrlen__,[
+# include <netinet/in.h>
+# ifdef INET6_ADDRSTRLEN
+ __has_inet6_addrstrlen__;
+# endif
+ ], [ol_cv_inet6_addrstrlen=yes], [ol_cv_inet6_addrstrlen=no])])
+
+ if test $ol_cv_inet6_addrstrlen = yes ; then
+ ol_link_ipv6=yes
+ elif test $ol_enable_ipv6 = yes ; then
+ AC_MSG_ERROR([IPv6 support requires INET6_ADDRSTRLEN])
+ fi
+fi
+
+if test $ol_enable_local != no ; then
+ AC_CHECK_HEADERS( sys/un.h )
+
+ if test $ol_enable_local = auto ; then
+ ol_enable_local=$ac_cv_header_sys_un_h
+ elif test $ac_cv_header_sys_un_h = no ; then
+ AC_MSG_ERROR([AF_LOCAL domain support requires sys/un.h])
+ fi
+fi
+