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  • dnl Process this file with autoconf to produce a configure script.
    
    AC_CONFIG_SRCDIR([ares_ipv6.h])
    
    AM_CONFIG_HEADER(config.h)
    AM_MAINTAINER_MODE
    AM_INIT_AUTOMAKE(c-ares, CVS)
    
    
    AC_PROG_CC
    AC_PROG_INSTALL
    
    case $host_os in
    solaris*)
    	AC_DEFINE(ETC_INET, 1, [if a /etc/inet dir is being used])
    	;;
    esac
    
    
    dnl support building of Windows DLLs
    
    AC_LIBTOOL_WIN32_DLL
    
    
    dnl ************************************************************
    dnl Option to switch on debug options. This makes an assumption that
    dnl this is built as an 'ares' subdir in the curl source tree. Subject for
    dnl improval in the future!
    dnl
    AC_MSG_CHECKING([whether to enable debug options])
    AC_ARG_ENABLE(debug,
    AC_HELP_STRING([--enable-debug],[Enable pedantic debug options])
    AC_HELP_STRING([--disable-debug],[Disable debug options]),
    [ case "$enableval" in
      no)
           AC_MSG_RESULT(no)
           ;;
      *)   AC_MSG_RESULT(yes)
    
        dnl when doing the debug stuff, use static library only
        AC_DISABLE_SHARED
    
        dnl the entire --enable-debug is a hack that lives and runs on top of
        dnl libcurl stuff so this BUILDING_LIBCURL is not THAT much uglier
        AC_DEFINE(BUILDING_LIBCURL, 1, [when building as static part of libcurl])
    
        CPPFLAGS="$CPPFLAGS -DCURLDEBUG -I$srcdir/../include"
        CFLAGS="$CFLAGS -g" 
    
    
        dnl check for how to do large files, needed to get the curl_off_t check
        dnl done right
        AC_SYS_LARGEFILE
    
        AC_CHECK_SIZEOF(curl_off_t, ,[
    #include <stdio.h>
    #include "$srcdir/../include/curl/curl.h"
        ])
    
    
        dnl set compiler "debug" options to become more picky, and remove
        dnl optimize options from CFLAGS
        CURL_CC_DEBUG_OPTS
    
           ;;
      esac ],
           AC_MSG_RESULT(no)
    )
    
    
    dnl skip libtool C++ and Fortran checks
    m4_undefine([AC_PROG_CXX])
    m4_defun([AC_PROG_CXX],[])
    m4_undefine([AC_PROG_F77])
    m4_defun([AC_PROG_F77],[])
    
    
    dnl libtool setup
    AC_PROG_LIBTOOL
    
    
    AC_MSG_CHECKING([if we need -no-undefined])
    case $host in
      *-*-cygwin | *-*-mingw* | *-*-pw32*)
        need_no_undefined=yes
        ;;
      *)
        need_no_undefined=no
        ;;
    esac
    AC_MSG_RESULT($need_no_undefined)
    AM_CONDITIONAL(NO_UNDEFINED, test x$need_no_undefined = xyes)
    
    
    dnl **********************************************************************
    dnl check if this is the Intel ICC compiler, and if so make it stricter
    dnl (convert warning 147 into an error) so that it properly can detect the
    dnl gethostbyname_r() version
    dnl **********************************************************************
    CURL_DETECT_ICC([CFLAGS="$CFLAGS -we 147"])
    
    
    dnl **********************************************************************
    dnl Checks for libraries.
    dnl **********************************************************************
    
    dnl gethostbyname without lib or in the nsl lib?
    AC_CHECK_FUNC(gethostbyname,
                  [HAVE_GETHOSTBYNAME="1"
                  ],
                  [ AC_CHECK_LIB(nsl, gethostbyname,
                                 [HAVE_GETHOSTBYNAME="1"
                                 LIBS="$LIBS -lnsl"
                                 ])
                  ])
    
    if test "$HAVE_GETHOSTBYNAME" != "1"
    then
      dnl gethostbyname in the socket lib?
      AC_CHECK_LIB(socket, gethostbyname,
                   [HAVE_GETHOSTBYNAME="1"
                   LIBS="$LIBS -lsocket"
                   ])
    fi
    
    dnl At least one system has been identified to require BOTH nsl and socket
    dnl libs at the same time to link properly.
    if test "$HAVE_GETHOSTBYNAME" != "1"
    then
      AC_MSG_CHECKING([for gethostbyname with both nsl and socket libs])
      my_ac_save_LIBS=$LIBS
      LIBS="-lnsl -lsocket $LIBS"
      AC_TRY_LINK( ,
                 [gethostbyname();],
                 [ dnl found it!
                 HAVE_GETHOSTBYNAME="1"
                 AC_MSG_RESULT([yes])],
                 [ dnl failed!
                 AC_MSG_RESULT([no])
                 dnl restore LIBS
                 LIBS=$my_ac_save_LIBS]
                 )
    fi
    
    if test "$HAVE_GETHOSTBYNAME" != "1"
    then
      dnl This is for Msys/Mingw
      AC_MSG_CHECKING([for gethostbyname in ws2_32])
      my_ac_save_LIBS=$LIBS
      LIBS="-lws2_32 $LIBS"
      AC_TRY_LINK([#include <winsock2.h>],
                   [gethostbyname("www.dummysite.com");],
                   [ dnl worked!
                   ws2="yes"
                   AC_MSG_RESULT([yes])
                   HAVE_GETHOSTBYNAME="1"],
                   [ dnl failed, restore LIBS
                   LIBS=$my_ac_save_LIBS
                   AC_MSG_RESULT(no)]
                 )
    fi
    
    if test "$HAVE_GETHOSTBYNAME" != "1"
    then
      dnl This is for eCos with a stubbed DNS implementation
      AC_MSG_CHECKING([for gethostbyname for eCos])
      AC_TRY_LINK([
    #include <stdio.h>
    #include <netdb.h>],
                   [gethostbyname("www.dummysite.com");],
                   [ dnl worked!
                   AC_MSG_RESULT([yes])
                   HAVE_GETHOSTBYNAME="1"],
                   AC_MSG_RESULT(no)
                 )
    fi
    
    if test "$HAVE_GETHOSTBYNAME" != "1"
    then
      dnl gethostbyname in the net lib - for BeOS
      AC_CHECK_LIB(net, gethostbyname,
                   [HAVE_GETHOSTBYNAME="1"
                   LIBS="$LIBS -lnet"
                   ])
    fi
    
    
    if test "$HAVE_GETHOSTBYNAME" = "1"; then
      AC_DEFINE(HAVE_GETHOSTBYNAME, 1, [If you have gethostbyname])
    else
      AC_MSG_ERROR([couldn't find libraries for gethostbyname()])
    fi
    
    
    dnl resolve lib?
    AC_CHECK_FUNC(strcasecmp, , [ AC_CHECK_LIB(resolve, strcasecmp) ])
    
    if test "$ac_cv_lib_resolve_strcasecmp" = "$ac_cv_func_strcasecmp"; then
      AC_CHECK_LIB(resolve, strcasecmp,
                  [LIBS="-lresolve $LIBS"],
                   ,
                   -lnsl)
    fi
    
    dnl socket lib?
    AC_CHECK_FUNC(connect, , [ AC_CHECK_LIB(socket, connect) ])
    
    dnl dl lib?
    AC_CHECK_FUNC(dlclose, , [ AC_CHECK_LIB(dl, dlopen) ])
    
    
    AC_MSG_CHECKING([whether to use libgcc])
    AC_ARG_ENABLE(libgcc,
    AC_HELP_STRING([--enable-libgcc],[use libgcc when linking]),
    [ case "$enableval" in
      yes)
            LIBS="$LIBS -lgcc"
           AC_MSG_RESULT(yes)
           ;;
      *)   AC_MSG_RESULT(no)
           ;;
      esac ],
           AC_MSG_RESULT(no)
    )
    
    
    
    dnl Default is to try the thread-safe versions of a few functions
    OPT_THREAD=on
    
    dnl detect AIX 4.3 or later
    AC_MSG_CHECKING([AIX 4.3 or later])
    AC_PREPROC_IFELSE([
    #if defined(_AIX) && defined(_AIX43)
    printf("just fine");
    #else
    #error "this is not AIX 4.3 or later"
    #endif
    ],
     [ AC_MSG_RESULT([yes])
       RECENTAIX=yes
       OPT_THREAD=off ],
     [ AC_MSG_RESULT([no]) ]
    )
    
    AC_ARG_ENABLE(thread,dnl
    AC_HELP_STRING([--disable-thread],[don't look for thread-safe functions])
    AC_HELP_STRING([--enable-thread],[look for thread-safe functions]),
    [ case "$enableval" in
      no)
        OPT_THREAD=off
        AC_MSG_WARN(c-ares will not get built using thread-safe functions)
        ;;
      *)
        ;;
      esac
    ]
    )
    
    if test X"$OPT_THREAD" = Xoff
    then
      AC_DEFINE(DISABLED_THREADSAFE, 1,
        [Set to explicitly specify we don't want to use thread-safe functions])
    fi
    
    dnl for recent AIX versions, we skip all the thread-safe checks above since
    dnl they claim a thread-safe libc using the standard API. But there are
    dnl some functions still not thread-safe. Check for these!
    
    dnl Let's hope this split URL remains working:
    dnl http://publibn.boulder.ibm.com/doc_link/en_US/a_doc_lib/aixprggd/ \
    dnl genprogc/thread_quick_ref.htm
    
    if test "x$RECENTAIX" = "xyes"; then
    
      AC_DEFINE(_THREAD_SAFE, 1, [define this if you need it to compile thread-safe code])
    
      dnl check if this is the IBM xlc compiler
      dnl Details thanks to => http://predef.sourceforge.net/
      AC_MSG_CHECKING([if this is the xlc compiler])
      AC_EGREP_CPP([^__xlC__], [__xlC__],
             dnl action if the text is found, this it has not been replaced by the
             dnl cpp
             XLC="no"
             AC_MSG_RESULT([no]),
             dnl the text was not found, it was replaced by the cpp
             XLC="yes"
             AC_MSG_RESULT([yes])
             CFLAGS="$CFLAGS -qthreaded"
             dnl AIX xlc has to have strict aliasing turned off. If not,
             dnl the optimizer assumes that pointers can only point to
             dnl an object of the same type.
             CFLAGS="$CFLAGS -qnoansialias"
           )
    fi
    
    
    
    dnl **********************************************************************
    dnl Back to "normal" configuring
    dnl **********************************************************************
    
    dnl Checks for header files.
    AC_HEADER_STDC
    
    dnl **********************************************************************
    dnl Make sure that our checks for headers windows.h winsock.h winsock2.h 
    dnl and ws2tcpip.h take precedence over any other further checks which 
    dnl could be done later using AC_CHECK_HEADER or AC_CHECK_HEADERS for
    
    dnl this specific header files. And do them before its results are used.
    
    dnl **********************************************************************
    
    CURL_CHECK_HEADER_WINDOWS
    CURL_CHECK_HEADER_WINSOCK
    CURL_CHECK_HEADER_WINSOCK2
    CURL_CHECK_HEADER_WS2TCPIP
    
    
    dnl check for a few basic system headers we need
    AC_CHECK_HEADERS(
           sys/types.h \
           sys/time.h \
           sys/select.h \
           sys/socket.h \
           sys/ioctl.h \
    
           arpa/inet.h,
    dnl to do if not found
    [],
    dnl to do if found
    [],
    dnl default includes
    
    [
    #ifdef HAVE_SYS_TYPES_H
    #include <sys/types.h>
    #endif
    
    #ifdef HAVE_SYS_TIME_H
    #include <sys/time.h>
    #endif
    
    dnl We do this default-include simply to make sure that the nameser_compat.h
    dnl header *REALLY* can be include after the new nameser.h. It seems AIX 5.1
    dnl (and others?) is not designed to allow this.
    #ifdef HAVE_ARPA_NAMESER_H
    #include <arpa/nameser.h>
    #endif
    
    dnl *Sigh* these are needed in order for net/if.h to get properly detected.
    #ifdef HAVE_SYS_SOCKET_H
    #include <sys/socket.h>
    #endif
    
    #ifdef HAVE_NETINET_IN_H
    #include <netinet/in.h>
    
    )
    
    dnl Checks for typedefs, structures, and compiler characteristics.
    AC_C_CONST
    AC_TYPE_SIZE_T
    AC_HEADER_TIME
    
    CURL_CHECK_STRUCT_TIMEVAL
    
    
    AC_CHECK_SIZEOF(size_t)
    AC_CHECK_SIZEOF(long)
    AC_CHECK_SIZEOF(time_t)
    
    AC_CHECK_TYPE(long long,
       [AC_DEFINE(HAVE_LONGLONG, 1, [if your compiler supports long long])]
       longlong="yes"  
    )
    
    if test "xyes" = "x$longlong"; then
      AC_MSG_CHECKING([if numberLL works])
      AC_COMPILE_IFELSE([long long val = 1000LL;],
       [AC_DEFINE(HAVE_LL, 1, [if your compiler supports LL])]
       AC_MSG_RESULT(yes),
       AC_MSG_RESULT(no)
    
    fi
    
    
    # check for ssize_t
    AC_CHECK_TYPE(ssize_t, ,
       AC_DEFINE(ssize_t, int, [the signed version of size_t]))
    
    # check for bool type
    AC_CHECK_TYPE([bool],[
      AC_DEFINE(HAVE_BOOL_T, 1,
        [Define to 1 if bool is an available type.])
    ], ,[
    
    #ifdef HAVE_SYS_TYPES_H
    #include <sys/types.h>
    #endif
    
    #ifdef HAVE_STDBOOL_H
    #include <stdbool.h>
    #endif
    ])
    
    
    # Check for socklen_t or equivalent
    CURL_CHECK_TYPE_SOCKLEN_T
    
    TYPE_IN_ADDR_T
    
    TYPE_SOCKADDR_STORAGE
    
    
    AC_TYPE_SIGNAL
    
    
    #undef inline
    #ifdef HAVE_WINDOWS_H
    #ifndef WIN32_LEAN_AND_MEAN
    #define WIN32_LEAN_AND_MEAN
    #endif
    #include <windows.h>
    #ifdef HAVE_WINSOCK2_H
    #include <winsock2.h>
    #endif
    #else
    
    #ifdef HAVE_SYS_TYPES_H
    #include <sys/types.h>
    #endif
    #ifdef HAVE_SYS_SOCKET_H
    #include <sys/socket.h>
    #endif
    #endif
      ], [PF_INET6], 
         AC_DEFINE_UNQUOTED(HAVE_PF_INET6,1,[Define to 1 if you have PF_INET6.])
    )
    
    dnl check for PF_INET6
    CARES_CHECK_CONSTANT(
      [
    
    #undef inline
    #ifdef HAVE_WINDOWS_H
    #ifndef WIN32_LEAN_AND_MEAN
    #define WIN32_LEAN_AND_MEAN
    #endif
    #include <windows.h>
    #ifdef HAVE_WINSOCK2_H
    #include <winsock2.h>
    #endif
    #else
    
    #ifdef HAVE_SYS_TYPES_H
    #include <sys/types.h>
    #endif
    #ifdef HAVE_SYS_SOCKET_H
    #include <sys/socket.h>
    #endif
    #endif
      ], [AF_INET6], 
         AC_DEFINE_UNQUOTED(HAVE_AF_INET6,1,[Define to 1 if you have AF_INET6.])
    )
    
    
    dnl check for the in6_addr structure
    CARES_CHECK_STRUCT(
      [
    
    #undef inline
    #ifdef HAVE_WINDOWS_H
    #ifndef WIN32_LEAN_AND_MEAN
    #define WIN32_LEAN_AND_MEAN
    
    #include <windows.h>
    
    #ifdef HAVE_WINSOCK2_H
    #include <winsock2.h>
    #ifdef HAVE_WS2TCPIP_H
    
    #endif
    #else
    #ifdef HAVE_SYS_TYPES_H
    #include <sys/types.h>
    #endif
    
    #ifdef HAVE_NETINET_IN_H
    #include <netinet/in.h>
    
    #endif
      ], [in6_addr], 
         AC_DEFINE_UNQUOTED(HAVE_STRUCT_IN6_ADDR,1,[Define to 1 if you have struct in6_addr.])
    )
    
    dnl check for the sockaddr_in6 structure
    CARES_CHECK_STRUCT(
      [
    
    #undef inline
    #ifdef HAVE_WINDOWS_H
    #ifndef WIN32_LEAN_AND_MEAN
    #define WIN32_LEAN_AND_MEAN
    
    #include <windows.h>
    
    #ifdef HAVE_WINSOCK2_H
    #include <winsock2.h>
    #ifdef HAVE_WS2TCPIP_H
    
    #endif
    #else
    #ifdef HAVE_SYS_TYPES_H
    #include <sys/types.h>
    #endif
    
    #ifdef HAVE_NETINET_IN_H
    #include <netinet/in.h>
    
    #endif
      ], [sockaddr_in6], 
         AC_DEFINE_UNQUOTED(HAVE_STRUCT_SOCKADDR_IN6,1,
           [Define to 1 if you have struct sockaddr_in6.]) ac_have_sockaddr_in6=yes
    )
    
    AC_CHECK_MEMBER(struct sockaddr_in6.sin6_scope_id,
        AC_DEFINE_UNQUOTED(HAVE_SOCKADDR_IN6_SIN6_SCOPE_ID,1,
          [Define to 1 if your struct sockaddr_in6 has sin6_scope_id.])
       , ,
      [
    
    #undef inline
    #ifdef HAVE_WINDOWS_H
    #ifndef WIN32_LEAN_AND_MEAN
    #define WIN32_LEAN_AND_MEAN
    
    #include <windows.h>
    
    #ifdef HAVE_WINSOCK2_H
    #include <winsock2.h>
    #ifdef HAVE_WS2TCPIP_H
    
    #endif
    #else
    #ifdef HAVE_SYS_TYPES_H
    #include <sys/types.h>
    #endif
    
    #ifdef HAVE_NETINET_IN_H
    #include <netinet/in.h>
    
    AC_CHECK_MEMBER(struct addrinfo.ai_flags,
         AC_DEFINE_UNQUOTED(HAVE_STRUCT_ADDRINFO,1,
           [Define to 1 if you have struct addrinfo.]),,
    
    #undef inline
    #ifdef HAVE_WINDOWS_H
    #ifndef WIN32_LEAN_AND_MEAN
    #define WIN32_LEAN_AND_MEAN
    
    #include <windows.h>
    #ifdef HAVE_WINSOCK2_H
    
    #include <winsock2.h>
    #ifdef HAVE_WS2TCPIP_H
    
    #endif
    #else
    #ifdef HAVE_SYS_TYPES_H
    #include <sys/types.h>
    #endif
    
    #ifdef HAVE_NETINET_IN_H
    #include <netinet/in.h>
    #endif
    
    #ifdef HAVE_SYS_SOCKET_H
    #include <sys/socket.h>
    #endif
    #ifdef HAVE_NETDB_H
    #include <netdb.h>
    
    AC_CHECK_FUNCS( bitncmp \
    
                    if_indextoname,
    dnl if found
    [],
    dnl if not found, $ac_func is the name we check for
    func="$ac_func"
    AC_MSG_CHECKING([deeper for $func])
    AC_TRY_LINK( [],
                 [ $func ();],
                 AC_MSG_RESULT(yes!)
                 eval "ac_cv_func_$func=yes"
                 def=`echo "HAVE_$func" | tr 'a-z' 'A-Z'`
                 AC_DEFINE_UNQUOTED($def, 1, [If you have $func]),
                 AC_MSG_RESULT(but still no)
                 )
    )
    
    
    
    dnl check for inet_pton
    AC_CHECK_FUNCS(inet_pton)
    dnl Some systems have it, but not IPv6
    if test "$ac_cv_func_inet_pton" = "yes" ; then
    AC_MSG_CHECKING(if inet_pton supports IPv6)
    AC_TRY_RUN(
      [
    #ifdef HAVE_SYS_TYPES_H
    #include <sys/types.h>
    #endif
    #ifdef HAVE_SYS_SOCKET_H
    #include <sys/socket.h>
    #endif
    #ifdef HAVE_NETINET_IN_H
    #include <netinet/in.h>
    #endif
    int main()
      {
        struct in6_addr addr6;
        if (inet_pton(AF_INET6, "::1", &addr6) < 1)
          exit(1);
        else
          exit(0);
      }
      ], [
           AC_MSG_RESULT(yes)
           AC_DEFINE_UNQUOTED(HAVE_INET_PTON_IPV6,1,[Define to 1 if inet_pton supports IPv6.])
         ], AC_MSG_RESULT(no),AC_MSG_RESULT(no))
    fi
    dnl Check for inet_net_pton
    AC_CHECK_FUNCS(inet_net_pton)
    dnl Again, some systems have it, but not IPv6
    if test "$ac_cv_func_inet_net_pton" = "yes" ; then
    AC_MSG_CHECKING(if inet_net_pton supports IPv6)
    AC_TRY_RUN(
      [
    #ifdef HAVE_SYS_TYPES_H
    #include <sys/types.h>
    #endif
    #ifdef HAVE_SYS_SOCKET_H
    #include <sys/socket.h>
    #endif
    #ifdef HAVE_NETINET_IN_H
    #include <netinet/in.h>
    #endif
    int main()
      {
        struct in6_addr addr6;
        if (inet_net_pton(AF_INET6, "::1", &addr6, sizeof(addr6)) < 1)
          exit(1);
        else
          exit(0);
      }
      ], [
           AC_MSG_RESULT(yes)
           AC_DEFINE_UNQUOTED(HAVE_INET_NET_PTON_IPV6,1,[Define to 1 if inet_net_pton supports IPv6.])
         ], AC_MSG_RESULT(no),AC_MSG_RESULT(no))
    fi
    
    
    dnl Check for inet_ntop
    AC_CHECK_FUNCS(inet_ntop)
    dnl Again, some systems have it, but not IPv6
    if test "$ac_cv_func_inet_ntop" = "yes" ; then
    AC_MSG_CHECKING(if inet_ntop supports IPv6)
    AC_TRY_RUN(
      [
    #ifdef HAVE_SYS_TYPES_H
    #include <sys/types.h>
    #endif
    #ifdef HAVE_SYS_SOCKET_H
    #include <sys/socket.h>
    #endif
    #ifdef HAVE_NETINET_IN_H
    #include <netinet/in.h>
    #endif
    #include <errno.h>
    int main()
      {
        struct in6_addr addr6;
        char buf[128];
        if (inet_ntop(AF_INET6, &addr6, buf, 128) == 0 && errno == EAFNOSUPPORT)
          exit(1);
        else
          exit(0);
      }
      ], [
           AC_MSG_RESULT(yes)
    
           AC_DEFINE_UNQUOTED(HAVE_INET_NTOP_IPV6,1,
              [Define to 1 if inet_ntop supports IPv6.])
    
         ], AC_MSG_RESULT(no),AC_MSG_RESULT(no))
    fi
    
    AC_CHECK_SIZEOF(struct in6_addr, ,
    [
    
    #undef inline
    #ifdef HAVE_WINDOWS_H
    #ifndef WIN32_LEAN_AND_MEAN
    #define WIN32_LEAN_AND_MEAN
    #endif
    #include <windows.h>
    #ifdef HAVE_WINSOCK2_H
    #include <winsock2.h>
    #ifdef HAVE_WS2TCPIP_H
    #include <ws2tcpip.h>
    #endif
    #endif
    #else
    
    #ifdef HAVE_SYS_TYPES_H
    #include <sys/types.h>
    #endif
    #ifdef HAVE_SYS_SOCKET_H
    #include <sys/socket.h>
    #endif
    #ifdef HAVE_NETINET_IN_H
    #include <netinet/in.h>
    #endif
    
    #undef inline
    #ifdef HAVE_WINDOWS_H
    #ifndef WIN32_LEAN_AND_MEAN
    #define WIN32_LEAN_AND_MEAN
    #endif
    #include <windows.h>
    #ifdef HAVE_WINSOCK2_H
    #include <winsock2.h>
    #ifdef HAVE_WS2TCPIP_H
    #include <ws2tcpip.h>
    #endif
    #endif
    #else
    
    #ifdef HAVE_SYS_TYPES_H
    #include <sys/types.h>
    #endif
    #ifdef HAVE_SYS_SOCKET_H
    #include <sys/socket.h>
    #endif
    #ifdef HAVE_NETINET_IN_H
    #include <netinet/in.h>
    #endif
    
    
    dnl Check if the getnameinfo function is available
    dnl and get the types of five of its arguments.
    CURL_CHECK_FUNC_GETNAMEINFO
    
    
    dnl God bless non-standardized functions! We need to see which getservbyport_r
    dnl variant is available
    
    CARES_CHECK_GETSERVBYPORT_R
    
    CURL_CHECK_NONBLOCKING_SOCKET
    
    
        [AC_DEFINE(ARES_BIG_ENDIAN, 1,
          [define this if ares is built for a big endian system])],
    
        ,
        [AC_MSG_WARN([couldn't figure out endianess, assuming little endian!])]
    )