configure.ac

         LIBS="$CLEANLIBS"
         CPPFLAGS="$CLEANCPPFLAGS"
       ])

      if test "x$USE_GNUTLS" = "xyes"; then
        AC_MSG_NOTICE([detected GnuTLS version $version])

        if test -n "$gtlslib"; then
          dnl when shared libs were found in a path that the run-time
          dnl linker doesn't search through, we need to add it to
          dnl LD_LIBRARY_PATH to prevent further configure tests to fail
          dnl due to this
          if test "x$cross_compiling" != "xyes"; then 
            LD_LIBRARY_PATH="$LD_LIBRARY_PATH:$gtlslib"
            export LD_LIBRARY_PATH
            AC_MSG_NOTICE([Added $gtlslib to LD_LIBRARY_PATH])
          fi
        fi
      fi

    fi

  fi dnl GNUTLS not disabled

fi

dnl ---
dnl Check which crypto backend GnuTLS uses
dnl ---

if test "$GNUTLS_ENABLED" = "1"; then
  USE_GNUTLS_NETTLE=
  # First check if we can detect either crypto library via transitive linking
  AC_CHECK_LIB(gnutls, nettle_MD5Init, [ USE_GNUTLS_NETTLE=1 ])
  if test "$USE_GNUTLS_NETTLE" = ""; then
    AC_CHECK_LIB(gnutls, gcry_control, [ USE_GNUTLS_NETTLE=0 ])
  fi
  # If not, try linking directly to both of them to see if they are available
  if test "$USE_GNUTLS_NETTLE" = ""; then
    AC_CHECK_LIB(nettle, nettle_MD5Init, [ USE_GNUTLS_NETTLE=1 ])
  fi
  if test "$USE_GNUTLS_NETTLE" = ""; then
    AC_CHECK_LIB(gcrypt, gcry_control, [ USE_GNUTLS_NETTLE=0 ])
  fi
  if test "$USE_GNUTLS_NETTLE" = ""; then
    AC_MSG_ERROR([GnuTLS found, but neither gcrypt nor nettle found])
  fi
  if test "$USE_GNUTLS_NETTLE" = "1"; then
    AC_DEFINE(USE_GNUTLS_NETTLE, 1, [if GnuTLS uses nettle as crypto backend])
    AC_SUBST(USE_GNUTLS_NETTLE, [1])
    LIBS="-lnettle $LIBS"
  else
    LIBS="-lgcrypt $LIBS"
  fi
fi

dnl ---
dnl We require GnuTLS with SRP support.
dnl ---
if test "$GNUTLS_ENABLED" = "1"; then
  AC_CHECK_LIB(gnutls, gnutls_srp_verifier,
   [
     AC_DEFINE(HAVE_GNUTLS_SRP, 1, [if you have the function gnutls_srp_verifier])
     AC_SUBST(HAVE_GNUTLS_SRP, [1])
   ])
fi

dnl ----------------------------------------------------
dnl check for PolarSSL
dnl ----------------------------------------------------

dnl Default to compiler & linker defaults for PolarSSL files & libraries.
OPT_POLARSSL=no

_cppflags=$CPPFLAGS
_ldflags=$LDFLAGS
AC_ARG_WITH(polarssl,dnl
AC_HELP_STRING([--with-polarssl=PATH],[where to look for PolarSSL, PATH points to the installation root])
AC_HELP_STRING([--without-polarssl], [disable PolarSSL detection]),
  OPT_POLARSSL=$withval)

if test "$curl_ssl_msg" = "$init_ssl_msg"; then

  if test X"$OPT_POLARSSL" != Xno; then

    if test "$OPT_POLARSSL" = "yes"; then
      OPT_POLARSSL=""
    fi

    if test -z "$OPT_POLARSSL" ; then
      dnl check for lib first without setting any new path

      AC_CHECK_LIB(polarssl, havege_init,
      dnl libpolarssl found, set the variable
       [
         AC_DEFINE(USE_POLARSSL, 1, [if PolarSSL is enabled])
         AC_SUBST(USE_POLARSSL, [1])
         POLARSSL_ENABLED=1
         USE_POLARSSL="yes"
         curl_ssl_msg="enabled (PolarSSL)"
        ])
    fi

    addld=""
    addlib=""
    addcflags=""
    polarssllib=""

    if test "x$USE_POLARSSL" != "xyes"; then
      dnl add the path and test again
      addld=-L$OPT_POLARSSL/lib$libsuff
      addcflags=-I$OPT_POLARSSL/include
      polarssllib=$OPT_POLARSSL/lib$libsuff

      LDFLAGS="$LDFLAGS $addld"
      if test "$addcflags" != "-I/usr/include"; then
         CPPFLAGS="$CPPFLAGS $addcflags"
      fi

      AC_CHECK_LIB(polarssl, ssl_init,
       [
       AC_DEFINE(USE_POLARSSL, 1, [if PolarSSL is enabled])
       AC_SUBST(USE_POLARSSL, [1])
       POLARSSL_ENABLED=1
       USE_POLARSSL="yes"
       curl_ssl_msg="enabled (PolarSSL)"
       ],
       [
         CPPFLAGS=$_cppflags
         LDFLAGS=$_ldflags
       ])
    fi

    if test "x$USE_POLARSSL" = "xyes"; then
      AC_MSG_NOTICE([detected PolarSSL])

      LIBS="-lpolarssl $LIBS"

      if test -n "$polarssllib"; then
        dnl when shared libs were found in a path that the run-time
        dnl linker doesn't search through, we need to add it to
        dnl LD_LIBRARY_PATH to prevent further configure tests to fail
        dnl due to this
        if test "x$cross_compiling" != "xyes"; then
          LD_LIBRARY_PATH="$LD_LIBRARY_PATH:$polarssllib"
          export LD_LIBRARY_PATH
          AC_MSG_NOTICE([Added $polarssllib to LD_LIBRARY_PATH])
        fi
      fi
    fi

  fi dnl PolarSSL not disabled

fi

dnl ----------------------------------------------------
dnl check for CyaSSL
dnl ----------------------------------------------------

dnl Default to compiler & linker defaults for CyaSSL files & libraries.
OPT_CYASSL=no

_cppflags=$CPPFLAGS
_ldflags=$LDFLAGS
AC_ARG_WITH(cyassl,dnl
AC_HELP_STRING([--with-cyassl=PATH],[where to look for CyaSSL, PATH points to the installation root (default: system lib default)])
AC_HELP_STRING([--without-cyassl], [disable CyaSSL detection]),
  OPT_CYASSL=$withval)

if test "$curl_ssl_msg" = "$init_ssl_msg"; then

  if test X"$OPT_CYASSL" != Xno; then

    if test "$OPT_CYASSL" = "yes"; then
      OPT_CYASSL=""
    fi

    if test -z "$OPT_CYASSL" ; then
      dnl check for lib in system default first

      AC_CHECK_LIB(cyassl, CyaSSL_Init,
      dnl libcyassl found, set the variable
       [
         AC_DEFINE(USE_CYASSL, 1, [if CyaSSL is enabled])
         AC_SUBST(USE_CYASSL, [1])
         CYASSL_ENABLED=1
         USE_CYASSL="yes"
         curl_ssl_msg="enabled (CyaSSL)"
        ])
    fi

    addld=""
    addlib=""
    addcflags=""
    cyassllib=""

    if test "x$USE_CYASSL" != "xyes"; then
      dnl add the path and test again
      addld=-L$OPT_CYASSL/lib$libsuff
      addcflags=-I$OPT_CYASSL/include
      cyassllib=$OPT_CYASSL/lib$libsuff

      LDFLAGS="$LDFLAGS $addld"
      if test "$addcflags" != "-I/usr/include"; then
         CPPFLAGS="$CPPFLAGS $addcflags"
      fi

      AC_CHECK_LIB(cyassl, CyaSSL_Init,
       [
       AC_DEFINE(USE_CYASSL, 1, [if CyaSSL is enabled])
       AC_SUBST(USE_CYASSL, [1])
       CYASSL_ENABLED=1
       USE_CYASSL="yes"
       curl_ssl_msg="enabled (CyaSSL)"
       ],
       [
         CPPFLAGS=$_cppflags
         LDFLAGS=$_ldflags
       ])
    fi

    if test "x$USE_CYASSL" = "xyes"; then
      AC_MSG_NOTICE([detected CyaSSL])

      LIBS="-lcyassl -lm $LIBS"

      if test -n "$cyassllib"; then
        dnl when shared libs were found in a path that the run-time
        dnl linker doesn't search through, we need to add it to
        dnl LD_LIBRARY_PATH to prevent further configure tests to fail
        dnl due to this
        if test "x$cross_compiling" != "xyes"; then
          LD_LIBRARY_PATH="$LD_LIBRARY_PATH:$cyassllib"
          export LD_LIBRARY_PATH
          AC_MSG_NOTICE([Added $cyassllib to LD_LIBRARY_PATH])
        fi
      fi

    fi

  fi dnl CyaSSL not disabled

fi

dnl ----------------------------------------------------
dnl NSS. Only check if GnuTLS and OpenSSL are not enabled
dnl ----------------------------------------------------

dnl Default to compiler & linker defaults for NSS files & libraries.
OPT_NSS=no

AC_ARG_WITH(nss,dnl
AC_HELP_STRING([--with-nss=PATH],[where to look for NSS, PATH points to the installation root])
AC_HELP_STRING([--without-nss], [disable NSS detection]),
  OPT_NSS=$withval)

if test "$curl_ssl_msg" = "$init_ssl_msg"; then

  if test X"$OPT_NSS" != Xno; then

    addld=""
    addlib=""
    addcflags=""
    nssprefix=""
    version=""

    if test "x$OPT_NSS" = "xyes"; then

      CURL_CHECK_PKGCONFIG(nss)

      if test "$PKGCONFIG" != "no" ; then
        addlib=`$PKGCONFIG --libs nss`
        addcflags=`$PKGCONFIG --cflags nss`
        version=`$PKGCONFIG --modversion nss`
        nssprefix=`$PKGCONFIG --variable=prefix nss`
      else
        dnl Without pkg-config, we check for nss-config

        check=`nss-config --version 2>/dev/null`
        if test -n "$check"; then
          addlib=`nss-config --libs`
          addcflags=`nss-config --cflags`
          version=`nss-config --version`
          nssprefix=`nss-config --prefix`
        else
          addlib="-lnss3"
          addcflags=""
          version="unknown"
        fi
      fi
    else
        # Without pkg-config, we'll kludge in some defaults
        addlib="-L$OPT_NSS/lib -lssl3 -lsmime3 -lnss3 -lplds4 -lplc4 -lnspr4 -lpthread -ldl"
        addcflags="-I$OPT_NSS/include"
        version="unknown"
        nssprefix=$OPT_NSS
    fi

    if test -n "$addlib"; then

      CLEANLIBS="$LIBS"
      CLEANCPPFLAGS="$CPPFLAGS"

      LIBS="$addlib $LIBS"
      if test "$addcflags" != "-I/usr/include"; then
         CPPFLAGS="$CPPFLAGS $addcflags"
      fi

      dnl The function PK11_CreateGenericObject is needed to load libnsspem.so
      AC_CHECK_LIB(nss3, PK11_CreateGenericObject,
       [
       AC_DEFINE(USE_NSS, 1, [if NSS is enabled])
       AC_SUBST(USE_NSS, [1])
       USE_NSS="yes"
       NSS_ENABLED=1
       curl_ssl_msg="enabled (NSS)"
       ],
       [
         LIBS="$CLEANLIBS"
         CPPFLAGS="$CLEANCPPFLAGS"
       ])

      if test "x$USE_NSS" = "xyes"; then
        AC_MSG_NOTICE([detected NSS version $version])

        dnl NSS_InitContext() was introduced in NSS 3.12.5 and helps to prevent
        dnl collisions on NSS initialization/shutdown with other libraries
        AC_CHECK_FUNC(NSS_InitContext,
        [
          AC_DEFINE(HAVE_NSS_INITCONTEXT, 1, [if you have the NSS_InitContext function])
          AC_SUBST(HAVE_NSS_INITCONTEXT, [1])
        ])

        dnl when shared libs were found in a path that the run-time
        dnl linker doesn't search through, we need to add it to
        dnl LD_LIBRARY_PATH to prevent further configure tests to fail
        dnl due to this
        if test "x$cross_compiling" != "xyes"; then
          LD_LIBRARY_PATH="$LD_LIBRARY_PATH:$nssprefix/lib$libsuff"
          export LD_LIBRARY_PATH
          AC_MSG_NOTICE([Added $nssprefix/lib$libsuff to LD_LIBRARY_PATH])
        fi
      fi

    fi

  fi dnl NSS not disabled

fi dnl curl_ssl_msg = init_ssl_msg

OPT_AXTLS=off

AC_ARG_WITH(axtls,dnl
AC_HELP_STRING([--with-axtls=PATH],[Where to look for axTLS, PATH points to the axTLS installation prefix (default: /usr/local).  Ignored if another SSL engine is selected.])
AC_HELP_STRING([--without-axtls], [disable axTLS]),
  OPT_AXTLS=$withval)

if test "$curl_ssl_msg" = "$init_ssl_msg"; then
  if test X"$OPT_AXTLS" != Xno; then
    dnl backup the pre-axtls variables
    CLEANLDFLAGS="$LDFLAGS"
    CLEANCPPFLAGS="$CPPFLAGS"
    CLEANLIBS="$LIBS"

    case "$OPT_AXTLS" in
    yes)
      dnl --with-axtls (without path) used
      PREFIX_AXTLS=/usr/local
      LIB_AXTLS="$PREFIX_AXTLS/lib"
      LDFLAGS="$LDFLAGS -L$LIB_AXTLS"
      CPPFLAGS="$CPPFLAGS -I$PREFIX_AXTLS/include"
      ;;
    off)
      dnl no --with-axtls option given, just check default places
      PREFIX_AXTLS=
      ;;
    *)
      dnl check the given --with-axtls spot
      PREFIX_AXTLS=$OPT_AXTLS
      LIB_AXTLS="$PREFIX_AXTLS/lib"
      LDFLAGS="$LDFLAGS -L$LIB_AXTLS"
      CPPFLAGS="$CPPFLAGS -I$PREFIX_AXTLS/include"
      ;;
    esac

    AC_CHECK_LIB(axtls, ssl_version,[
      LIBS="-laxtls $LIBS"
      AC_DEFINE(USE_AXTLS, 1, [if axTLS is enabled])
      AC_SUBST(USE_AXTLS, [1])
      AXTLS_ENABLED=1
      USE_AXTLS="yes"
      curl_ssl_msg="enabled (axTLS)"


      LD_LIBRARY_PATH="$LD_LIBRARY_PATH:$LIB_AXTLS"
      export LD_LIBRARY_PATH
      AC_MSG_NOTICE([Added $LIB_AXTLS to LD_LIBRARY_PATH])
      ],[
      LDFLAGS="$CLEANLDFLAGS"
      CPPFLAGS="$CLEANCPPFLAGS"
      LIBS="$CLEANLIBS"
    ])
  fi
fi

if test "x$OPENSSL_ENABLED$GNUTLS_ENABLED$NSS_ENABLED$POLARSSL_ENABLED$AXTLS_ENABLED$CYASSL_ENABLED$WINSSL_ENABLED$DARWINSSL_ENABLED" = "x"; then
  AC_MSG_WARN([SSL disabled, you will not be able to use HTTPS, FTPS, NTLM and more.])
  AC_MSG_WARN([Use --with-ssl, --with-gnutls, --with-polarssl, --with-cyassl, --with-nss, --with-axtls or --with-winssl to address this.])
else
  # SSL is enabled, genericly
  AC_SUBST(SSL_ENABLED)
  SSL_ENABLED="1"
fi

dnl **********************************************************************
dnl Check for the CA bundle
dnl **********************************************************************

CURL_CHECK_CA_BUNDLE

dnl **********************************************************************
dnl Check for libmetalink
dnl **********************************************************************

OPT_LIBMETALINK=no

AC_ARG_WITH(libmetalink,dnl
AC_HELP_STRING([--with-libmetalink=PATH],[where to look for libmetalink, PATH points to the installation root])
AC_HELP_STRING([--without-libmetalink], [disable libmetalink detection]),
  OPT_LIBMETALINK=$withval)

if test X"$OPT_LIBMETALINK" != Xno; then

  addld=""
  addlib=""
  addcflags=""
  version=""
  libmetalinklib=""

  PKGTEST="no"
  if test "x$OPT_LIBMETALINK" = "xyes"; then
    dnl this is with no partiular path given
    PKGTEST="yes"
    CURL_CHECK_PKGCONFIG(libmetalink)
  else
    dnl When particular path is given, set PKG_CONFIG_LIBDIR using the path.
    LIBMETALINK_PCDIR="$OPT_LIBMETALINK/lib/pkgconfig"
    AC_MSG_NOTICE([PKG_CONFIG_LIBDIR will be set to "$LIBMETALINK_PCDIR"])
    if test -f "$LIBMETALINK_PCDIR/libmetalink.pc"; then
      PKGTEST="yes"
    fi
    if test "$PKGTEST" = "yes"; then
      CURL_CHECK_PKGCONFIG(libmetalink, [$LIBMETALINK_PCDIR])
    fi
  fi
  if test "$PKGTEST" = "yes" && test "$PKGCONFIG" != "no"; then
    addlib=`CURL_EXPORT_PCDIR([$LIBMETALINK_PCDIR]) dnl
      $PKGCONFIG --libs-only-l libmetalink`
    addld=`CURL_EXPORT_PCDIR([$LIBMETALINK_PCDIR]) dnl
      $PKGCONFIG --libs-only-L libmetalink`
    addcflags=`CURL_EXPORT_PCDIR([$LIBMETALINK_PCDIR]) dnl
      $PKGCONFIG --cflags-only-I libmetalink`
    version=`CURL_EXPORT_PCDIR([$LIBMETALINK_PCDIR]) dnl
      $PKGCONFIG --modversion libmetalink`
    libmetalinklib=`echo $addld | $SED -e 's/-L//'`
  fi
  if test -n "$addlib"; then

    clean_CPPFLAGS="$CPPFLAGS"
    clean_LDFLAGS="$LDFLAGS"
    clean_LIBS="$LIBS"
    CPPFLAGS="$addcflags $clean_CPPFLAGS"
    LDFLAGS="$addld $clean_LDFLAGS"
    LIBS="$addlib $clean_LIBS"
    AC_MSG_CHECKING([if libmetalink is recent enough])
    AC_LINK_IFELSE([
      AC_LANG_PROGRAM([[
#       include <metalink/metalink.h>
      ]],[[
        if(0 != metalink_strerror(0)) /* added in 0.1.0 */
          return 1;
      ]])
    ],[
      AC_MSG_RESULT([yes ($version)])
      want_metalink="yes"
    ],[
      AC_MSG_RESULT([no ($version)])
      AC_MSG_NOTICE([libmetalink library defective or too old])
      want_metalink="no"
    ])
    CPPFLAGS="$clean_CPPFLAGS"
    LDFLAGS="$clean_LDFLAGS"
    LIBS="$clean_LIBS"
    if test "$want_metalink" = "yes"; then
      dnl finally libmetalink will be used
      AC_DEFINE(USE_METALINK, 1, [Define to enable metalink support])
      LIBMETALINK_LIBS=$addlib
      LIBMETALINK_LDFLAGS=$addld
      LIBMETALINK_CPPFLAGS=$addcflags
      AC_SUBST([LIBMETALINK_LIBS])
      AC_SUBST([LIBMETALINK_LDFLAGS])
      AC_SUBST([LIBMETALINK_CPPFLAGS])
      curl_mtlnk_msg="enabled"
    fi

  fi
fi

dnl **********************************************************************
dnl Check for the presence of LIBSSH2 libraries and headers
dnl **********************************************************************

dnl Default to compiler & linker defaults for LIBSSH2 files & libraries.
OPT_LIBSSH2=off
AC_ARG_WITH(libssh2,dnl
AC_HELP_STRING([--with-libssh2=PATH],[Where to look for libssh2, PATH points to the LIBSSH2 installation; when possible, set the PKG_CONFIG_PATH environment variable instead of using this option])
AC_HELP_STRING([--without-libssh2], [disable LIBSSH2]),
  OPT_LIBSSH2=$withval)

if test X"$OPT_LIBSSH2" != Xno; then
  dnl backup the pre-libssh2 variables
  CLEANLDFLAGS="$LDFLAGS"
  CLEANCPPFLAGS="$CPPFLAGS"
  CLEANLIBS="$LIBS"

  case "$OPT_LIBSSH2" in
  yes)
    dnl --with-libssh2 (without path) used
    CURL_CHECK_PKGCONFIG(libssh2)

    if test "$PKGCONFIG" != "no" ; then
      LIB_SSH2=`$PKGCONFIG --libs-only-l libssh2`
      LD_SSH2=`$PKGCONFIG --libs-only-L libssh2`
      CPP_SSH2=`$PKGCONFIG --cflags-only-I libssh2`
      version=`$PKGCONFIG --modversion libssh2`
      DIR_SSH2=`echo $LD_SSH2 | $SED -e 's/-L//'`
    fi

    ;;
  off)
    dnl no --with-libssh2 option given, just check default places
    ;;
  *)
    dnl use the given --with-libssh2 spot
    PREFIX_SSH2=$OPT_LIBSSH2
    ;;
  esac

  dnl if given with a prefix, we set -L and -I based on that
  if test -n "$PREFIX_SSH2"; then
    LIB_SSH2="-lssh2"
    LD_SSH2=-L${PREFIX_SSH2}/lib$libsuff
    CPP_SSH2=-I${PREFIX_SSH2}/include
    DIR_SSH2=${PREFIX_SSH2}/lib$libsuff
  fi

  LDFLAGS="$LDFLAGS $LD_SSH2"
  CPPFLAGS="$CPPFLAGS $CPP_SSH2"
  LIBS="$LIB_SSH2 $LIBS"

  AC_CHECK_LIB(ssh2, libssh2_channel_open_ex)

  AC_CHECK_HEADERS(libssh2.h,
    curl_ssh_msg="enabled (libSSH2)"
    LIBSSH2_ENABLED=1
    AC_DEFINE(USE_LIBSSH2, 1, [if libSSH2 is in use])
    AC_SUBST(USE_LIBSSH2, [1])
  )

  if test X"$OPT_LIBSSH2" != Xoff &&
     test "$LIBSSH2_ENABLED" != "1"; then
    AC_MSG_ERROR([libSSH2 libs and/or directories were not found where specified!])
  fi

  if test "$LIBSSH2_ENABLED" = "1"; then
    if test -n "$DIR_SSH2"; then
       dnl when the libssh2 shared libs were found in a path that the run-time
       dnl linker doesn't search through, we need to add it to LD_LIBRARY_PATH
       dnl to prevent further configure tests to fail due to this

       dnl libssh2_version is a post 1.0 addition
       dnl libssh2_init and libssh2_exit were added in 1.2.5
       dnl libssh2_scp_send64 was added in 1.2.6
       dnl libssh2_session_handshake was added in 1.2.8
       AC_CHECK_FUNCS( libssh2_version libssh2_init libssh2_exit \
                       libssh2_scp_send64 libssh2_session_handshake)
       if test "x$cross_compiling" != "xyes"; then
         LD_LIBRARY_PATH="$LD_LIBRARY_PATH:$DIR_SSH2"
         export LD_LIBRARY_PATH
         AC_MSG_NOTICE([Added $DIR_SSH2 to LD_LIBRARY_PATH])
       fi
    fi
  else
    dnl no libssh2, revert back to clean variables
    LDFLAGS=$CLEANLDFLAGS
    CPPFLAGS=$CLEANCPPFLAGS
    LIBS=$CLEANLIBS
  fi
fi

dnl **********************************************************************
dnl Check for the presence of LIBRTMP libraries and headers
dnl **********************************************************************

dnl Default to compiler & linker defaults for LIBRTMP files & libraries.
OPT_LIBRTMP=off
AC_ARG_WITH(librtmp,dnl
AC_HELP_STRING([--with-librtmp=PATH],[Where to look for librtmp, PATH points to the LIBRTMP installation; when possible, set the PKG_CONFIG_PATH environment variable instead of using this option])
AC_HELP_STRING([--without-librtmp], [disable LIBRTMP]),
  OPT_LIBRTMP=$withval)

if test X"$OPT_LIBRTMP" != Xno; then
  dnl backup the pre-librtmp variables
  CLEANLDFLAGS="$LDFLAGS"
  CLEANCPPFLAGS="$CPPFLAGS"
  CLEANLIBS="$LIBS"

  case "$OPT_LIBRTMP" in
  yes)
    dnl --with-librtmp (without path) used
    CURL_CHECK_PKGCONFIG(librtmp)

    if test "$PKGCONFIG" != "no" ; then
      LIB_RTMP=`$PKGCONFIG --libs-only-l librtmp`
      LD_RTMP=`$PKGCONFIG --libs-only-L librtmp`
      CPP_RTMP=`$PKGCONFIG --cflags-only-I librtmp`
      version=`$PKGCONFIG --modversion librtmp`
      DIR_RTMP=`echo $LD_RTMP | $SED -e 's/-L//'`
    else
      dnl To avoid link errors, we do not allow --librtmp without
      dnl a pkgconfig file
      AC_MSG_ERROR([--librtmp was specified but could not find librtmp pkgconfig file.])
    fi

    ;;
  off)
    dnl no --with-librtmp option given, just check default places
    LIB_RTMP="-lrtmp"
    ;;
  *)
    dnl use the given --with-librtmp spot
    PREFIX_RTMP=$OPT_LIBRTMP
    ;;
  esac

  dnl if given with a prefix, we set -L and -I based on that
  if test -n "$PREFIX_RTMP"; then
    LD_RTMP=-L${PREFIX_RTMP}/lib$libsuff
    CPP_RTMP=-I${PREFIX_RTMP}/include
    DIR_RTMP=${PREFIX_RTMP}/lib$libsuff
  fi

  LDFLAGS="$LDFLAGS $LD_RTMP"
  CPPFLAGS="$CPPFLAGS $CPP_RTMP"
  LIBS="$LIB_RTMP $LIBS"

  AC_CHECK_LIB(rtmp, RTMP_Init,
    [
     AC_CHECK_HEADERS(librtmp/rtmp.h,
        curl_rtmp_msg="enabled (librtmp)"
        LIBRTMP_ENABLED=1
        AC_DEFINE(USE_LIBRTMP, 1, [if librtmp is in use])
        AC_SUBST(USE_LIBRTMP, [1])
     )
    ],
      dnl not found, revert back to clean variables
      LDFLAGS=$CLEANLDFLAGS
      CPPFLAGS=$CLEANCPPFLAGS
      LIBS=$CLEANLIBS
  )

  if test X"$OPT_LIBRTMP" != Xoff &&
     test "$LIBRTMP_ENABLED" != "1"; then
    AC_MSG_ERROR([librtmp libs and/or directories were not found where specified!])
  fi

fi

dnl **********************************************************************
dnl Check for linker switch for versioned symbols
dnl **********************************************************************

versioned_symbols_flavour=
AC_MSG_CHECKING([whether versioned symbols are wanted])
AC_ARG_ENABLE(versioned-symbols,
AC_HELP_STRING([--enable-versioned-symbols], [Enable versioned symbols in shared library])
AC_HELP_STRING([--disable-versioned-symbols], [Disable versioned symbols in shared library]),
[ case "$enableval" in
  yes) AC_MSG_RESULT(yes)
    AC_MSG_CHECKING([if libraries can be versioned])
    GLD=`$LD --help < /dev/null 2>/dev/null | grep version-script`
    if test -z "$GLD"; then
        AC_MSG_RESULT(no)
        AC_MSG_WARN([You need an ld version supporting the --version-script option])
    else
        AC_MSG_RESULT(yes)
        if test "x$OPENSSL_ENABLED" = "x1"; then
          versioned_symbols_flavour="OPENSSL_"
        elif test "x$GNUTLS_ENABLED" == "x1"; then
          versioned_symbols_flavour="GNUTLS_"
        elif test "x$NSS_ENABLED" == "x1"; then
          versioned_symbols_flavour="NSS_"
        elif test "x$POLARSSL_ENABLED" == "x1"; then
          versioned_symbols_flavour="POLARSSL_"
        elif test "x$CYASSL_ENABLED" == "x1"; then
          versioned_symbols_flavour="CYASSL_"
        elif test "x$AXTLS_ENABLED" == "x1"; then
          versioned_symbols_flavour="AXTLS_"
        elif test "x$WINSSL_ENABLED" == "x1"; then
          versioned_symbols_flavour="WINSSL_"
        elif test "x$DARWINSSL_ENABLED" == "x1"; then
          versioned_symbols_flavour="DARWINSSL_"
        else
          versioned_symbols_flavour=""
        fi
        versioned_symbols="yes"
    fi
    ;;

  *)   AC_MSG_RESULT(no)
    ;;
  esac
], [
AC_MSG_RESULT(no)
]
)

AC_SUBST(VERSIONED_FLAVOUR, ["$versioned_symbols_flavour"])
AM_CONDITIONAL(VERSIONED_SYMBOLS, test "x$versioned_symbols" = "xyes")

dnl -------------------------------------------------
dnl check winidn option before other IDN libraries
dnl -------------------------------------------------

AC_MSG_CHECKING([whether to enable Windows native IDN (Windows native builds only)])
OPT_WINIDN="default"
AC_ARG_WITH(winidn,
AC_HELP_STRING([--with-winidn=PATH],[enable Windows native IDN])
AC_HELP_STRING([--without-winidn], [disable Windows native IDN]),
  OPT_WINIDN=$withval)
case "$OPT_WINIDN" in
  no|default)
    dnl --without-winidn option used or configure option not specified
    want_winidn="no"
    AC_MSG_RESULT([no])
    ;;
  yes)
    dnl --with-winidn option used without path
    want_winidn="yes"
    want_winidn_path="default"
    AC_MSG_RESULT([yes])
    ;;
  *)
    dnl --with-winidn option used with path
    want_winidn="yes"
    want_winidn_path="$withval"
    AC_MSG_RESULT([yes ($withval)])
    ;;
esac

if test "$want_winidn" = "yes"; then
  dnl winidn library support has been requested
  clean_CPPFLAGS="$CPPFLAGS"
  clean_LDFLAGS="$LDFLAGS"
  clean_LIBS="$LIBS"
  WINIDN_LIBS="-lnormaliz"
  #
  if test "$want_winidn_path" != "default"; then
    dnl path has been specified
    dnl pkg-config not available or provides no info
    WINIDN_LDFLAGS="-L$want_winidn_path/lib$libsuff"
    WINIDN_CPPFLAGS="-I$want_winidn_path/include"
    WINIDN_DIR="$want_winidn_path/lib$libsuff"
  fi
  #
  CPPFLAGS="$WINIDN_CPPFLAGS $CPPFLAGS"
  LDFLAGS="$WINIDN_LDFLAGS $LDFLAGS"
  LIBS="$WINIDN_LIBS $LIBS"
  #
  AC_MSG_CHECKING([if IdnToUnicode can be linked])
  AC_LINK_IFELSE([
    AC_LANG_FUNC_LINK_TRY([IdnToUnicode])
  ],[
    AC_MSG_RESULT([yes])
    tst_links_winidn="yes"
  ],[
    AC_MSG_RESULT([no])
    tst_links_winidn="no"
  ])
  #
  if test "$tst_links_winidn" = "yes"; then
    AC_DEFINE(USE_WIN32_IDN, 1, [Define to 1 if you have the `normaliz' (WinIDN) library (-lnormaliz).])
    AC_DEFINE(WANT_IDN_PROTOTYPES, 1, [Define to 1 to provide own prototypes.])
    AC_SUBST([IDN_ENABLED], [1])
    curl_idn_msg="enabled (Windows-native)"
  else
    AC_MSG_WARN([Cannot find libraries for IDN support: IDN disabled])
    CPPFLAGS="$clean_CPPFLAGS"
    LDFLAGS="$clean_LDFLAGS"
    LIBS="$clean_LIBS"
  fi
fi

dnl **********************************************************************
dnl Check for the presence of IDN libraries and headers
dnl **********************************************************************

AC_MSG_CHECKING([whether to build with libidn])
OPT_IDN="default"
AC_ARG_WITH(libidn,
AC_HELP_STRING([--with-libidn=PATH],[Enable libidn usage])
AC_HELP_STRING([--without-libidn],[Disable libidn usage]),
  [OPT_IDN=$withval])
case "$OPT_IDN" in
  no)
    dnl --without-libidn option used
    want_idn="no"
    AC_MSG_RESULT([no])
    ;;
  default)
    dnl configure option not specified
    want_idn="yes"
    want_idn_path="default"
    AC_MSG_RESULT([(assumed) yes])
    ;;
  yes)
    dnl --with-libidn option used without path
    want_idn="yes"
    want_idn_path="default"
    AC_MSG_RESULT([yes])
    ;;
  *)
    dnl --with-libidn option used with path
    want_idn="yes"
    want_idn_path="$withval"
    AC_MSG_RESULT([yes ($withval)])
    ;;
esac

if test "$want_idn" = "yes"; then
  dnl idn library support has been requested
  clean_CPPFLAGS="$CPPFLAGS"
  clean_LDFLAGS="$LDFLAGS"
  clean_LIBS="$LIBS"
  PKGCONFIG="no"
  #
  if test "$want_idn_path" != "default"; then
    dnl path has been specified
    IDN_PCDIR="$want_idn_path/lib$libsuff/pkgconfig"
    CURL_CHECK_PKGCONFIG(libidn, [$IDN_PCDIR])
    if test "$PKGCONFIG" != "no"; then
      IDN_LIBS=`CURL_EXPORT_PCDIR([$IDN_PCDIR]) dnl
        $PKGCONFIG --libs-only-l libidn 2>/dev/null`
      IDN_LDFLAGS=`CURL_EXPORT_PCDIR([$IDN_PCDIR]) dnl
        $PKGCONFIG --libs-only-L libidn 2>/dev/null`
      IDN_CPPFLAGS=`CURL_EXPORT_PCDIR([$IDN_PCDIR]) dnl
        $PKGCONFIG --cflags-only-I libidn 2>/dev/null`
      IDN_DIR=`echo $IDN_LDFLAGS | $SED -e 's/-L//'`
    else
      dnl pkg-config not available or provides no info
      IDN_LIBS="-lidn"
      IDN_LDFLAGS="-L$want_idn_path/lib$libsuff"
      IDN_CPPFLAGS="-I$want_idn_path/include"
      IDN_DIR="$want_idn_path/lib$libsuff"
    fi
  else
    dnl path not specified
    CURL_CHECK_PKGCONFIG(libidn)
    if test "$PKGCONFIG" != "no"; then
      IDN_LIBS=`$PKGCONFIG --libs-only-l libidn 2>/dev/null`
      IDN_LDFLAGS=`$PKGCONFIG --libs-only-L libidn 2>/dev/null`
      IDN_CPPFLAGS=`$PKGCONFIG --cflags-only-I libidn 2>/dev/null`
      IDN_DIR=`echo $IDN_LDFLAGS | $SED -e 's/-L//'`
    else
      dnl pkg-config not available or provides no info
      IDN_LIBS="-lidn"
    fi
  fi
  #
  if test "$PKGCONFIG" != "no"; then
    AC_MSG_NOTICE([pkg-config: IDN_LIBS: "$IDN_LIBS"])
    AC_MSG_NOTICE([pkg-config: IDN_LDFLAGS: "$IDN_LDFLAGS"])
    AC_MSG_NOTICE([pkg-config: IDN_CPPFLAGS: "$IDN_CPPFLAGS"])
    AC_MSG_NOTICE([pkg-config: IDN_DIR: "$IDN_DIR"])
  else
    AC_MSG_NOTICE([IDN_LIBS: "$IDN_LIBS"])
    AC_MSG_NOTICE([IDN_LDFLAGS: "$IDN_LDFLAGS"])
    AC_MSG_NOTICE([IDN_CPPFLAGS: "$IDN_CPPFLAGS"])
    AC_MSG_NOTICE([IDN_DIR: "$IDN_DIR"])
  fi
  #
  CPPFLAGS="$IDN_CPPFLAGS $CPPFLAGS"
  LDFLAGS="$IDN_LDFLAGS $LDFLAGS"
  LIBS="$IDN_LIBS $LIBS"
  #
  AC_MSG_CHECKING([if idna_to_ascii_4i can be linked])
  AC_LINK_IFELSE([
    AC_LANG_FUNC_LINK_TRY([idna_to_ascii_4i])
  ],[
    AC_MSG_RESULT([yes])
    tst_links_libidn="yes"
  ],[
    AC_MSG_RESULT([no])
    tst_links_libidn="no"
  ])
  if test "$tst_links_libidn" = "no"; then
    AC_MSG_CHECKING([if idna_to_ascii_lz can be linked])
    AC_LINK_IFELSE([
      AC_LANG_FUNC_LINK_TRY([idna_to_ascii_lz])
    ],[
      AC_MSG_RESULT([yes])
      tst_links_libidn="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_links_libidn="no"
    ])
  fi
  #
  if test "$tst_links_libidn" = "yes"; then
    AC_DEFINE(HAVE_LIBIDN, 1, [Define to 1 if you have the `idn' library (-lidn).])
    dnl different versions of libidn have different setups of these:
    AC_CHECK_FUNCS( idn_free idna_strerror tld_strerror )
    AC_CHECK_HEADERS( idn-free.h tld.h )
    if test "x$ac_cv_header_tld_h" = "xyes"; then
      AC_SUBST([IDN_ENABLED], [1])
      curl_idn_msg="enabled"
      if test -n "$IDN_DIR"; then
        LD_LIBRARY_PATH="$LD_LIBRARY_PATH:$IDN_DIR"
        export LD_LIBRARY_PATH
        AC_MSG_NOTICE([Added $IDN_DIR to LD_LIBRARY_PATH])
      fi
    else
      AC_MSG_WARN([Libraries for IDN support too old: IDN disabled])
      CPPFLAGS="$clean_CPPFLAGS"
      LDFLAGS="$clean_LDFLAGS"
      LIBS="$clean_LIBS"
    fi
  else
    AC_MSG_WARN([Cannot find libraries for IDN support: IDN disabled])
    CPPFLAGS="$clean_CPPFLAGS"
    LDFLAGS="$clean_LDFLAGS"
    LIBS="$clean_LIBS"
  fi
fi


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


dnl **********************************************************************
dnl Back to "normal" configuring
dnl **********************************************************************

dnl Checks for header files.
AC_HEADER_STDC

CURL_CHECK_HEADER_MALLOC
CURL_CHECK_HEADER_MEMORY

dnl Now check for the very most basic headers. Then we can use these
dnl ones as default-headers when checking for the rest!
AC_CHECK_HEADERS(
        sys/types.h \
        sys/time.h \
        sys/select.h \
        sys/socket.h \
        sys/ioctl.h \
        sys/uio.h \
        assert.h \
        unistd.h \
        stdlib.h \
        limits.h \
        arpa/inet.h \
        net/if.h \
        netinet/in.h \
        sys/un.h \
        netinet/tcp.h \
        netdb.h \
        sys/sockio.h \
        sys/stat.h \
        sys/param.h \
        termios.h \
        termio.h \
        sgtty.h \
        fcntl.h \
        alloca.h \
        time.h \
        io.h \
        pwd.h \
        utime.h \
        sys/utime.h \
        sys/poll.h \
        poll.h \
        socket.h \
        sys/resource.h \
        libgen.h \
        locale.h \
        errno.h \