configure.ac

      AC_DEFINE(HAVE_KRB4, 1,
      [if you have the Kerberos4 libraries (including -ldes)])

      dnl substitute it too!
      KRB4_ENABLED=1
      AC_SUBST(KRB4_ENABLED)

      curl_krb4_msg="enabled"

      dnl the krb4 stuff needs a strlcpy()
      AC_CHECK_FUNCS(strlcpy)

    ])
  ])
else
  AC_MSG_RESULT(no)
fi

dnl **********************************************************************
dnl Check for FBopenssl(SPNEGO) libraries
dnl **********************************************************************

AC_ARG_WITH(spnego,
  AC_HELP_STRING([--with-spnego=DIR],
                 [Specify location of SPNEGO library fbopenssl]), [
  SPNEGO_ROOT="$withval"
  if test x"$SPNEGO_ROOT" != xno; then
    want_spnego="yes"
  fi
])

AC_MSG_CHECKING([if SPNEGO support is requested])
if test x"$want_spnego" = xyes; then

  if test X"$SPNEGO_ROOT" = Xyes; then
     AC_MSG_ERROR([FBOpenSSL libs and/or directories were not found where specified!])
     AC_MSG_RESULT(no)
  else
     if test -z "$SPNEGO_LIB_DIR"; then
        LDFLAGS="$LDFLAGS -L$SPNEGO_ROOT -lfbopenssl"
     else
        LDFLAGS="$LDFLAGS $SPNEGO_LIB_DIR"
     fi

     AC_MSG_RESULT(yes)
     AC_DEFINE(HAVE_SPNEGO, 1,
               [Define this if you have the SPNEGO library fbopenssl])
     curl_spnego_msg="enabled"
  fi
else
  AC_MSG_RESULT(no)
fi

dnl **********************************************************************
dnl Check for GSS-API libraries
dnl **********************************************************************

dnl check for gss stuff in the /usr as default

GSSAPI_ROOT="/usr"
AC_ARG_WITH(gssapi-includes,
  AC_HELP_STRING([--with-gssapi-includes=DIR],
                 [Specify location of GSSAPI header]),
  [ GSSAPI_INCS="-I$withval"
    want_gss="yes" ]
)

AC_ARG_WITH(gssapi-libs,
  AC_HELP_STRING([--with-gssapi-libs=DIR],
                 [Specify location of GSSAPI libs]),
  [ GSSAPI_LIB_DIR="-L$withval"
    want_gss="yes" ]
)

AC_ARG_WITH(gssapi,
  AC_HELP_STRING([--with-gssapi=DIR],
                 [Where to look for GSSAPI]), [
  GSSAPI_ROOT="$withval"
  if test x"$GSSAPI_ROOT" != xno; then
    want_gss="yes"
    if test x"$GSSAPI_ROOT" = xyes; then
      dnl if yes, then use default root
      GSSAPI_ROOT="/usr"
    fi
  fi
])

save_CPPFLAGS="$CPPFLAGS"
AC_MSG_CHECKING([if GSSAPI support is requested])
if test x"$want_gss" = xyes; then
  AC_MSG_RESULT(yes)

  if test -z "$GSSAPI_INCS"; then
     if test -f "$GSSAPI_ROOT/bin/krb5-config"; then
        GSSAPI_INCS=`$GSSAPI_ROOT/bin/krb5-config --cflags gssapi`
        GSSAPI_LIBS=`$GSSAPI_ROOT/bin/krb5-config --libs gssapi`
     elif test "$GSSAPI_ROOT" != "yes"; then
        GSSAPI_INCS="-I$GSSAPI_ROOT/include"
        GSSAPI_LIBS="-lgssapi"
     fi
  fi

  CPPFLAGS="$CPPFLAGS $GSSAPI_INCS"
  LIBS="$LIBS $GSSAPI_LIBS"

  AC_CHECK_HEADER(gss.h,
    [
      dnl found in the given dirs
      AC_DEFINE(HAVE_GSSGNU, 1, [if you have the GNU gssapi libraries])
      gnu_gss=yes
    ],
    [
      dnl not found, check Heimdal or MIT
      AC_CHECK_HEADERS(
        [gssapi/gssapi.h gssapi/gssapi_generic.h gssapi/gssapi_krb5.h],
        [],
        [not_mit=1])
      if test "x$not_mit" = "x1"; then
        dnl MIT not found, check for Heimdal
        AC_CHECK_HEADER(gssapi.h,
            [
              dnl found
              AC_DEFINE(HAVE_GSSHEIMDAL, 1, [if you have the Heimdal gssapi libraries])
            ],
            [
              dnl no header found, disabling GSS
              want_gss=no
              AC_MSG_WARN(disabling GSSAPI since no header files was found)
            ]
          )
      else
        dnl MIT found
        AC_DEFINE(HAVE_GSSMIT, 1, [if you have the MIT gssapi libraries])
        dnl check if we have a really old MIT kerberos (<= 1.2)
        AC_MSG_CHECKING([if gssapi headers declare GSS_C_NT_HOSTBASED_SERVICE])
        AC_COMPILE_IFELSE([
          AC_LANG_PROGRAM([[
#include <gssapi/gssapi.h>
#include <gssapi/gssapi_generic.h>
#include <gssapi/gssapi_krb5.h>
          ]],[[
            gss_import_name(
                            (OM_uint32 *)0,
                            (gss_buffer_t)0,
                            GSS_C_NT_HOSTBASED_SERVICE,
                            (gss_name_t *)0);
          ]])
        ],[
          AC_MSG_RESULT([yes])
        ],[
          AC_MSG_RESULT([no])
          AC_DEFINE(HAVE_OLD_GSSMIT, 1,
            [if you have an old MIT gssapi library, lacking GSS_C_NT_HOSTBASED_SERVICE])
        ])
      fi
    ]
  )
else
  AC_MSG_RESULT(no)
fi
if test x"$want_gss" = xyes; then
  AC_DEFINE(HAVE_GSSAPI, 1, [if you have the gssapi libraries])

  curl_gss_msg="enabled (MIT/Heimdal)"

  if test -n "$gnu_gss"; then
    curl_gss_msg="enabled (GNU GSS)"
    LDFLAGS="$LDFLAGS $GSSAPI_LIB_DIR"
    LIBS="$LIBS -lgss"
  elif test -z "$GSSAPI_LIB_DIR"; then
     if test -f "$GSSAPI_ROOT/bin/krb5-config"; then
        dnl krb5-config doesn't have --libs-only-L or similar, put everything
        dnl into LIBS
        gss_libs=`$GSSAPI_ROOT/bin/krb5-config --libs gssapi`
        LIBS="$LIBS $gss_libs"
     elif test "$GSSAPI_ROOT" != "yes"; then
        LDFLAGS="$LDFLAGS -L$GSSAPI_ROOT/lib$libsuff"
        LIBS="$LIBS -lgssapi"
     else
        LIBS="$LIBS -lgssapi"
     fi
  else
     LDFLAGS="$LDFLAGS $GSSAPI_LIB_DIR"
     LIBS="$LIBS -lgssapi"
  fi
else
  CPPFLAGS="$save_CPPFLAGS"
fi

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

dnl Default to compiler & linker defaults for SSL files & libraries.
OPT_SSL=off
dnl Default to no CA bundle
ca="no"
AC_ARG_WITH(ssl,dnl
AC_HELP_STRING([--with-ssl=PATH],[Where to look for OpenSSL, PATH points to the SSL installation (default: /usr/local/ssl); when possible, set the PKG_CONFIG_PATH environment variable instead of using this option])
AC_HELP_STRING([--without-ssl], [disable OpenSSL]),
  OPT_SSL=$withval)

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

  case "$OPT_SSL" in
  yes)
    dnl --with-ssl (without path) used
    if test x$cross_compiling != xyes; then
      dnl only do pkg-config magic when not cross-compiling
      PKGTEST="yes"
    fi
    PREFIX_OPENSSL=/usr/local/ssl
    LIB_OPENSSL="$PREFIX_OPENSSL/lib$libsuff"
    ;;
  off)
    dnl no --with-ssl option given, just check default places
    if test x$cross_compiling != xyes; then
      dnl only do pkg-config magic when not cross-compiling
      PKGTEST="yes"
    fi
    PREFIX_OPENSSL=
    ;;
  *)
    dnl check the given --with-ssl spot
    PKGTEST="no"
    PREFIX_OPENSSL=$OPT_SSL
    LIB_OPENSSL="$PREFIX_OPENSSL/lib$libsuff"
    LDFLAGS="$LDFLAGS -L$LIB_OPENSSL"
    CPPFLAGS="$CPPFLAGS -I$PREFIX_OPENSSL/include/openssl -I$PREFIX_OPENSSL/include"
    ;;
  esac

  if test "$PKGTEST" = "yes"; then

    dnl Detect the pkg-config tool, as it may have extra info about the
    dnl openssl installation we can use. I *believe* this is what we are
    dnl expected to do on really recent Redhat Linux hosts.

    AC_PATH_PROG( PKGCONFIG, pkg-config, no, $PATH:/usr/bin:/usr/local/bin)
    if test "$PKGCONFIG" != "no" ; then
      AC_MSG_CHECKING([OpenSSL options with pkg-config])

      $PKGCONFIG --exists openssl
      SSL_EXISTS=$?

      if test "$SSL_EXISTS" -eq "0"; then
        SSL_LIBS=`$PKGCONFIG --libs-only-l openssl 2>/dev/null`
        SSL_LDFLAGS=`$PKGCONFIG --libs-only-L openssl 2>/dev/null`
        SSL_CPPFLAGS=`$PKGCONFIG --cflags-only-I openssl 2>/dev/null`

        LIB_OPENSSL=`echo $SSL_LDFLAGS | sed -e 's/-L//g'`

        dnl use the values pkg-config reported
        LIBS="$LIBS $SSL_LIBS"
        CPPFLAGS="$CPPFLAGS $SSL_CPPFLAGS"
        LDFLAGS="$LDFLAGS $SSL_LDFLAGS"
        AC_MSG_RESULT([found])
      else
        AC_MSG_RESULT([no])
      fi
    fi
  fi

  AC_CHECK_LIB(crypto, CRYPTO_lock,[
     HAVECRYPTO="yes"
     LIBS="-lcrypto $LIBS"
     ],[
     LDFLAGS="$CLEANLDFLAGS -L$LIB_OPENSSL"
     CPPFLAGS="$CLEANCPPFLAGS -I$PREFIX_OPENSSL/include/openssl -I$PREFIX_OPENSSL/include"
     AC_CHECK_LIB(crypto, CRYPTO_add_lock,[
       HAVECRYPTO="yes"
       LIBS="-lcrypto $LIBS"], [
       LDFLAGS="$CLEANLDFLAGS"
       CPPFLAGS="$CLEANCPPFLAGS"
       LIBS="$CLEANLIBS"
       ])
    ])


  if test X"$HAVECRYPTO" = X"yes"; then
    dnl This is only reasonable to do if crypto actually is there: check for
    dnl SSL libs NOTE: it is important to do this AFTER the crypto lib

    AC_CHECK_LIB(ssl, SSL_connect)

    if test "$ac_cv_lib_ssl_SSL_connect" != yes; then
        dnl we didn't find the SSL lib, try the RSAglue/rsaref stuff
        AC_MSG_CHECKING(for ssl with RSAglue/rsaref libs in use);
        OLIBS=$LIBS
        LIBS="$LIBS -lRSAglue -lrsaref"
        AC_CHECK_LIB(ssl, SSL_connect)
        if test "$ac_cv_lib_ssl_SSL_connect" != yes; then
            dnl still no SSL_connect
            AC_MSG_RESULT(no)
            LIBS=$OLIBS
        else
            AC_MSG_RESULT(yes)
        fi

    else

      dnl Have the libraries--check for SSLeay/OpenSSL headers
      AC_CHECK_HEADERS(openssl/x509.h openssl/rsa.h openssl/crypto.h \
                       openssl/pem.h openssl/ssl.h openssl/err.h,
        curl_ssl_msg="enabled (OpenSSL)"
        OPENSSL_ENABLED=1
        AC_DEFINE(USE_OPENSSL, 1, [if OpenSSL is in use]))

      if test $ac_cv_header_openssl_x509_h = no; then
        dnl we don't use the "action" part of the AC_CHECK_HEADERS macro
        dnl since 'err.h' might in fact find a krb4 header with the same
        dnl name
        AC_CHECK_HEADERS(x509.h rsa.h crypto.h pem.h ssl.h err.h)

        if test $ac_cv_header_x509_h = yes &&
           test $ac_cv_header_crypto_h = yes &&
           test $ac_cv_header_ssl_h = yes; then
          dnl three matches
          curl_ssl_msg="enabled (OpenSSL)"
          OPENSSL_ENABLED=1
        fi
      fi
    fi

    if test X"$OPENSSL_ENABLED" = X"1"; then
       AC_DEFINE(USE_SSLEAY, 1, [if SSL is enabled])

       dnl is there a pkcs12.h header present?
       AC_CHECK_HEADERS(openssl/pkcs12.h)
    else
       LIBS="$CLEANLIBS"
    fi
    dnl USE_SSLEAY is the historical name for what configure calls
    dnl OPENSSL_ENABLED; the names should really be unified
    USE_SSLEAY="$OPENSSL_ENABLED"
    AC_SUBST(USE_SSLEAY)

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

  if test X"$OPENSSL_ENABLED" = X"1"; then
    dnl If the ENGINE library seems to be around, check for the OpenSSL engine
    dnl stuff, it is kind of "separated" from the main SSL check
    AC_CHECK_FUNC(ENGINE_init,
              [
                AC_CHECK_HEADERS(openssl/engine.h)
                AC_CHECK_FUNCS( ENGINE_load_builtin_engines )
              ])

    dnl these can only exist if openssl exists
    dnl yassl doesn't have SSL_get_shutdown

    AC_CHECK_FUNCS( RAND_status \
                    RAND_screen \
                    RAND_egd \
                    CRYPTO_cleanup_all_ex_data \
                    SSL_get_shutdown )

    dnl Make an attempt to detect if this is actually yassl's headers and
    dnl OpenSSL emulation layer. We still leave everything else believing
    dnl and acting like OpenSSL.

    AC_MSG_CHECKING([for yaSSL using OpenSSL compatibility mode])
    AC_COMPILE_IFELSE([
      AC_LANG_PROGRAM([[
#include <openssl/ssl.h>
      ]],[[
#if defined(YASSL_VERSION) && defined(OPENSSL_VERSION_NUMBER)
        int dummy = SSL_ERROR_NONE;
#else
        Not the yaSSL OpenSSL compatibility header.
#endif
      ]])
    ],[
      AC_MSG_RESULT([yes])
      AC_DEFINE_UNQUOTED(USE_YASSLEMUL, 1,
        [Define to 1 if using yaSSL in OpenSSL compatibility mode.])
      curl_ssl_msg="enabled (OpenSSL emulation by yaSSL)"
    ],[
      AC_MSG_RESULT([no])
    ])
  fi

  if test "$OPENSSL_ENABLED" = "1"; then
    if test -n "$LIB_OPENSSL"; then
       dnl when the ssl 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

       LD_LIBRARY_PATH="$LD_LIBRARY_PATH:$LIB_OPENSSL"
       export LD_LIBRARY_PATH
       AC_MSG_NOTICE([Added $LIB_OPENSSL to LD_LIBRARY_PATH])
    fi
  fi

fi

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

dnl Check for & handle argument to --with-zlib.

_cppflags=$CPPFLAGS
_ldflags=$LDFLAGS
AC_ARG_WITH(zlib,
AC_HELP_STRING([--with-zlib=PATH],[search for zlib in PATH])
AC_HELP_STRING([--without-zlib],[disable use of zlib]),
               [OPT_ZLIB="$withval"])

if test "$OPT_ZLIB" = "no" ; then
    AC_MSG_WARN([zlib disabled])
else
  if test "$OPT_ZLIB" = "yes" ; then
     OPT_ZLIB=""
  fi

  if test -z "$OPT_ZLIB" ; then
    dnl check for the lib first without setting any new path, since many
    dnl people have it in the default path

    AC_CHECK_LIB(z, inflateEnd,
                   dnl libz found, set the variable
                   [HAVE_LIBZ="1"],
                   dnl if no lib found, try /usr/local
                   [OPT_ZLIB="/usr/local"])

  fi

  dnl Add a nonempty path to the compiler flags
  if test -n "$OPT_ZLIB"; then
     CPPFLAGS="$CPPFLAGS -I$OPT_ZLIB/include"
     LDFLAGS="$LDFLAGS -L$OPT_ZLIB/lib$libsuff"
  fi

  AC_CHECK_HEADER(zlib.h,
    [
    dnl zlib.h was found
    HAVE_ZLIB_H="1"
    dnl if the lib wasn't found already, try again with the new paths
    if test "$HAVE_LIBZ" != "1"; then
      AC_CHECK_LIB(z, gzread,
                   [
                   dnl the lib was found!
                   HAVE_LIBZ="1"
                   ],
                   [ CPPFLAGS=$_cppflags
                   LDFLAGS=$_ldflags])
    fi
    ],
    [
      dnl zlib.h was not found, restore the flags
      CPPFLAGS=$_cppflags
      LDFLAGS=$_ldflags]
    )

  if test "$HAVE_LIBZ" = "1" && test "$HAVE_ZLIB_H" != "1"
  then
    AC_MSG_WARN([configure found only the libz lib, not the header file!])
    HAVE_LIBZ=""
  elif test "$HAVE_LIBZ" != "1" && test "$HAVE_ZLIB_H" = "1"
  then
    AC_MSG_WARN([configure found only the libz header file, not the lib!])
  elif test "$HAVE_LIBZ" = "1" && test "$HAVE_ZLIB_H" = "1"
  then
    dnl both header and lib were found!
    AC_SUBST(HAVE_LIBZ)
    AC_DEFINE(HAVE_ZLIB_H, 1, [if you have the zlib.h header file])
    AC_DEFINE(HAVE_LIBZ, 1, [if zlib is available])

    CURL_LIBS="$CURL_LIBS -lz"
    LIBS="$LIBS -lz"

    dnl replace 'HAVE_LIBZ' in the automake makefile.ams
    AMFIXLIB="1"
    AC_MSG_NOTICE([found both libz and libz.h header])
    curl_zlib_msg="enabled"
  fi
fi

dnl set variable for use in automakefile(s)
AM_CONDITIONAL(HAVE_LIBZ, test x"$AMFIXLIB" = x1)

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 (default: /usr/local/lib); 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 "$OPT_LIBSSH2" in
  yes)
    dnl --with-libssh2 (without path) used
    PREFIX_LIBSSH2=/usr/local/lib
    LIB_LIBSSH2="$PREFIX_LIBSSH2$libsuff"
    ;;
  off)
    dnl no --with-libssh2 option given, just check default places
    PREFIX_LIBSSH2=
    ;;
  *)
    dnl use the given --with-libssh2 spot
    PREFIX_LIBSSH2=$OPT_LIBSSH2
    LIB_LIBSSH2="$PREFIX_LIBSSH2/lib$libsuff"
    LDFLAGS="$LDFLAGS -L$LIB_LIBSSH2"
    CPPFLAGS="$CPPFLAGS -I$PREFIX_LIBSSH2/include"
    ;;
  esac

  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 "$LIBSSH2_ENABLED" = "1"; then
    if test -n "$LIB_LIBSSH2"; 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

       LD_LIBRARY_PATH="$LD_LIBRARY_PATH:$LIB_LIBSSH2"
       export LD_LIBRARY_PATH
       AC_MSG_NOTICE([Added $LIB_LIBSSH2 to LD_LIBRARY_PATH])
    fi
  fi
fi

dnl **********************************************************************
dnl Check for the random seed preferences
dnl **********************************************************************

if test X"$OPENSSL_ENABLED" = X"1"; then
  AC_ARG_WITH(egd-socket,
  AC_HELP_STRING([--with-egd-socket=FILE],
                 [Entropy Gathering Daemon socket pathname]),
      [ EGD_SOCKET="$withval" ]
  )
  if test -n "$EGD_SOCKET" ; then
          AC_DEFINE_UNQUOTED(EGD_SOCKET, "$EGD_SOCKET",
          [your Entropy Gathering Daemon socket pathname] )
  fi

  dnl Check for user-specified random device
  AC_ARG_WITH(random,
  AC_HELP_STRING([--with-random=FILE],
                 [read randomness from FILE (default=/dev/urandom)]),
      [ RANDOM_FILE="$withval" ],
      [
          dnl Check for random device
          AC_CHECK_FILE("/dev/urandom", [ RANDOM_FILE="/dev/urandom"] )
      ]
  )
  if test -n "$RANDOM_FILE" && test X"$RANDOM_FILE" != Xno ; then
          AC_SUBST(RANDOM_FILE)
          AC_DEFINE_UNQUOTED(RANDOM_FILE, "$RANDOM_FILE",
          [a suitable file to read random data from])
  fi
fi

dnl ----------------------------------------------------
dnl FIX: only check for GnuTLS if OpenSSL is not enabled
dnl ----------------------------------------------------

dnl Default to compiler & linker defaults for GnuTLS files & libraries.
OPT_GNUTLS=no

AC_ARG_WITH(gnutls,dnl
AC_HELP_STRING([--with-gnutls=PATH],[where to look for GnuTLS, PATH points to the installation root (default: /usr/local/)])
AC_HELP_STRING([--without-gnutls], [disable GnuTLS detection]),
  OPT_GNUTLS=$withval)

if test "$OPENSSL_ENABLED" != "1"; then

  if test X"$OPT_GNUTLS" != Xno; then
    if test "x$OPT_GNUTLS" = "xyes"; then
     check=`libgnutls-config --version 2>/dev/null`
     if test -n "$check"; then
       addlib=`libgnutls-config --libs`
       addcflags=`libgnutls-config --cflags`
       version=`libgnutls-config --version`
       gtlsprefix=`libgnutls-config --prefix`
     fi
    else
      addlib=`$OPT_GNUTLS/bin/libgnutls-config --libs`
      addcflags=`$OPT_GNUTLS/bin/libgnutls-config --cflags`
      version=`$OPT_GNUTLS/bin/libgnutls-config --version 2>/dev/null`
      gtlsprefix=$OPT_GNUTLS
      if test -z "$version"; then
        version="unknown"
      fi
    fi
    if test -n "$addlib"; then

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

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

      AC_CHECK_LIB(gnutls, gnutls_check_version,
       [
       AC_DEFINE(USE_GNUTLS, 1, [if GnuTLS is enabled])
       AC_SUBST(USE_GNUTLS, [1])
       GNUTLS_ENABLED=1
       USE_GNUTLS="yes"
       curl_ssl_msg="enabled (GnuTLS)"
       ],
       [
         LIBS="$CLEANLIBS"
         CPPFLAGS="$CLEANCPPFLAGS"
       ])

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

        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

        LD_LIBRARY_PATH="$LD_LIBRARY_PATH:$gtlsprefix/lib$libsuff"
        export LD_LIBRARY_PATH
        AC_MSG_NOTICE([Added $gtlsprefix/lib$libsuff to LD_LIBRARY_PATH])
      fi

    fi

  fi dnl GNUTLS not disabled

fi dnl OPENSSL != 1

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 (default: /usr/local/)])
AC_HELP_STRING([--without-nss], [disable NSS detection]),
  OPT_NSS=$withval)

if test "$OPENSSL_ENABLED" != "1" -a "$GNUTLS_ENABLED" != "1"; then

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

    dnl Check for functionPK11_CreateGenericObject
    dnl this is needed for using the PEM PKCS#11 module
    AC_CHECK_LIB(nss3, PK11_CreateGenericObject,
     [
     AC_DEFINE(HAVE_PK11_CREATEGENERICOBJECT, 1, [if you have the function PK11_CreateGenericObject])
     AC_SUBST(HAVE_PK11_CREATEGENERICOBJECT, [1])
     ])
    if test -n "$addlib"; then

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

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

      AC_CHECK_LIB(nss3, NSS_Initialize,
       [
       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 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

        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 dnl NSS not disabled

fi dnl OPENSSL != 1 -a GNUTLS_ENABLED != 1

if test "x$OPENSSL_ENABLED$GNUTLS_ENABLED$NSS_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 or --with-nss 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 the presence of IDN libraries and headers
dnl **********************************************************************

AC_MSG_CHECKING([whether to build with libidn])
AC_ARG_WITH(libidn,
AC_HELP_STRING([--with-libidn=PATH],[Enable libidn usage])
AC_HELP_STRING([--without-libidn],[Disable libidn usage]),
  [LIBIDN="$withval"])

case "$LIBIDN" in
  no)
       AC_MSG_RESULT(no)
       ;;
  *)   AC_MSG_RESULT(yes)

       idn=""
       dnl if there is a given path, check that FIRST
       if test -n "$LIBIDN"; then
         if test "x$LIBIDN" != "xyes"; then
            oldLDFLAGS=$LDFLAGS
            oldCPPFLAGS=$CPPFLAGS
            LDFLAGS="$LDFLAGS -L$LIBIDN/lib"
            CPPFLAGS="$CPPFLAGS -I$LIBIDN/include"
            idn="yes"
            AC_CHECK_LIB(idn, idna_to_ascii_4i, ,
                         idn=""
                         LDFLAGS=$oldLDFLAGS
                         CPPFLAGS=$oldCPPFLAGS)
         fi
       fi

       if test "x$idn" != "xyes"; then
          dnl check with default paths
          idn="yes"
          AC_CHECK_LIB(idn, idna_to_ascii_lz, ,
                       idn="")
       fi

       if test "x$idn" = "xyes"; then
         curl_idn_msg="enabled"
         AC_SUBST(IDN_ENABLED, [1])
         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 )
       fi

       ;;
esac

dnl Default is to try the thread-safe versions of a few functions
OPT_THREAD=on

dnl detect AIX 4.3 or later
dnl see full docs on this reasoning in the lib/hostip.c source file
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(libcurl will not get built using thread-safe functions)
    ;;
  *)
    ;;
  esac
]
)

if test X"$OPT_THREAD" = Xoff
then
  AC_DEFINE(DISABLED_THREADSAFE, 1,
    [Set to explicitly specify we don't want to use thread-safe functions])
else
  if test "$ipv6" != "yes"; then
    dnl dig around for gethostbyname_r()
    CURL_CHECK_GETHOSTBYNAME_R()

    dnl dig around for gethostbyaddr_r()
    dnl CURL_CHECK_GETHOSTBYADDR_R()
  fi

  dnl poke around for inet_ntoa_r()
  CURL_CHECK_INET_NTOA_R()

  dnl is there a localtime_r()
  CURL_CHECK_LOCALTIME_R()

  dnl is there a strerror_r()
  dnl the old strerror_r check was done here

  checkfor_gmtime_r="yes"
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 is there a localtime_r()
  CURL_CHECK_LOCALTIME_R()

  dnl is there a strerror_r()
  dnl the old strerror_r check was done here

  checkfor_gmtime_r="yes"
fi


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

dnl Checks for header files.
AC_HEADER_STDC

CURL_CHECK_HEADER_MALLOC

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 \
        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 \
        sys/resource.h \
        libgen.h \
        locale.h \
        errno.h \
        stdbool.h \
        arpa/tftp.h \
        sys/filio.h \
        setjmp.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
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#ifdef HAVE_SYS_UN_H
#include <sys/un.h>
#endif
]
)

dnl Checks for typedefs, structures, and compiler characteristics.
AC_C_CONST
CURL_CHECK_VARIADIC_MACROS
AC_TYPE_SIZE_T
AC_HEADER_TIME
CURL_CHECK_STRUCT_TIMEVAL
CURL_VERIFY_RUNTIMELIBS

AC_CHECK_SIZEOF(size_t)
AC_CHECK_SIZEOF(int)
AC_CHECK_SIZEOF(long)
CURL_CONFIGURE_LONG
AC_CHECK_SIZEOF(time_t)
AC_CHECK_SIZEOF(off_t)

soname_bump=no
if test x"$ac_cv_native_windows" != "xyes" &&
   test $ac_cv_sizeof_off_t -ne $curl_sizeof_curl_off_t; then
  AC_MSG_WARN([This libcurl built is probably not ABI compatible with previous])
  AC_MSG_WARN([builds! You MUST read lib/README.curl_off_t to figure it out.])
  soname_bump=yes
fi


AC_CHECK_TYPE(long long,
   [AC_DEFINE(HAVE_LONGLONG, 1,
      [Define to 1 if the compiler supports the 'long long' data type.])]
   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