configure: avoid usage of macro PKG_CHECK_MODULES

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]),

  [LIBIDN="$withval"])

case "$LIBIDN" in

  [OPT_IDN=$withval])

case "$OPT_IDN" in

  no)

       AC_MSG_RESULT(no)

    dnl --without-libidn option used

    want_idn="no"

    AC_MSG_RESULT([no])

    ;;

  *)   AC_MSG_RESULT(yes)

  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

       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)

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

       if test "x$idn" != "xyes"; then

         dnl to prevent errors with pkg-config < 0.26

         m4_pattern_allow(PKG_CONFIG_LIBDIR)

         dnl check with pkg-config

         PKG_CHECK_MODULES(LIBIDN_PC, libidn >= 0.0.0, [idn=yes], [idn=no])

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

            LIBS="$LIBS $LIBIDN_PC_LIBS"

            CPPFLAGS="$CPPFLAGS $LIBIDN_PC_CFLAGS"

  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

       if test "x$idn" != "xyes"; then

          dnl check with default paths

          idn="yes"

          AC_CHECK_LIB(idn, idna_to_ascii_lz, ,

                       idn="")

  #

  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 "x$idn" = "xyes"; then

         curl_idn_msg="enabled"

         AC_SUBST(IDN_ENABLED, [1])

  #

  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

       ;;

esac

dnl Let's hope this split URL remains working: