text: # pkg.m4 - Macros to locate and utilise pkg-config.            -*- Autoconf -*-
  #
  # Copyright © 2004 Scott James Remnant <scott@netsplit.com>.
  #
  # This program is free software; you can redistribute it and/or modify
  # it under the terms of the GNU General Public License as published by
  # the Free Software Foundation; either version 2 of the License, or
  # (at your option) any later version.
  #
  # This program is distributed in the hope that it will be useful, but
  # WITHOUT ANY WARRANTY; without even the implied warranty of
  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  # General Public License for more details.
  #
  # You should have received a copy of the GNU General Public License
  # along with this program; if not, write to the Free Software
  # Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  #
  # As a special exception to the GNU General Public License, if you
  # distribute this file as part of a program that contains a
  # configuration script generated by Autoconf, you may include it under
  # the same distribution terms that you use for the rest of that program.
  
  # PKG_PROG_PKG_CONFIG([MIN-VERSION])
  # ----------------------------------
  AC_DEFUN([PKG_PROG_PKG_CONFIG],
  [m4_pattern_forbid([^_?PKG_[A-Z_]+$])
  m4_pattern_allow([^PKG_CONFIG(_PATH)?$])
  AC_ARG_VAR([PKG_CONFIG], [path to pkg-config utility])dnl
  if test "x$ac_cv_env_PKG_CONFIG_set" != "xset"; then
  	AC_PATH_TOOL([PKG_CONFIG], [pkg-config])
  fi
  if test -n "$PKG_CONFIG"; then
  	_pkg_min_version=m4_default([$1], [0.9.0])
  	AC_MSG_CHECKING([pkg-config is at least version $_pkg_min_version])
  	if $PKG_CONFIG --atleast-pkgconfig-version $_pkg_min_version; then
  		AC_MSG_RESULT([yes])
  	else
  		AC_MSG_RESULT([no])
  		PKG_CONFIG=""
  	fi
  
  fi[]dnl
  ])# PKG_PROG_PKG_CONFIG
  
  # PKG_CHECK_EXISTS(MODULES, [ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND])
  #
  # Check to see whether a particular set of modules exists.  Similar
  # to PKG_CHECK_MODULES(), but does not set variables or print errors.
  #
  #
  # Similar to PKG_CHECK_MODULES, make sure that the first instance of
  # this or PKG_CHECK_MODULES is called, or make sure to call
  # PKG_CHECK_EXISTS manually
  # --------------------------------------------------------------
  AC_DEFUN([PKG_CHECK_EXISTS],
  [AC_REQUIRE([PKG_PROG_PKG_CONFIG])dnl
  if test -n "$PKG_CONFIG" && \
      AC_RUN_LOG([$PKG_CONFIG --exists --print-errors "$1"]); then
    m4_ifval([$2], [$2], [:])
  m4_ifvaln([$3], [else
    $3])dnl
  fi])
  
  
  # _PKG_CONFIG([VARIABLE], [COMMAND], [MODULES])
  # ---------------------------------------------
  m4_define([_PKG_CONFIG],
  [if test -n "$PKG_CONFIG"; then
      if test -n "$$1"; then
          pkg_cv_[]$1="$$1"
      else
          PKG_CHECK_EXISTS([$3],
                           [pkg_cv_[]$1=`$PKG_CONFIG --[]$2 "$3" 2>/dev/null`],
  			 [pkg_failed=yes])
      fi
  else
  	pkg_failed=untried
  fi[]dnl
  ])# _PKG_CONFIG
  
  # _PKG_SHORT_ERRORS_SUPPORTED
  # -----------------------------
  AC_DEFUN([_PKG_SHORT_ERRORS_SUPPORTED],
  [AC_REQUIRE([PKG_PROG_PKG_CONFIG])
  if $PKG_CONFIG --atleast-pkgconfig-version 0.20; then
          _pkg_short_errors_supported=yes
  else
          _pkg_short_errors_supported=no
  fi[]dnl
  ])# _PKG_SHORT_ERRORS_SUPPORTED
  
  
  # PKG_CHECK_MODULES(VARIABLE-PREFIX, MODULES, [ACTION-IF-FOUND],
  # [ACTION-IF-NOT-FOUND])
  #
  #
  # Note that if there is a possibility the first call to
  # PKG_CHECK_MODULES might not happen, you should be sure to include an
  # explicit call to PKG_PROG_PKG_CONFIG in your configure.ac
  #
  #
  # --------------------------------------------------------------
  AC_DEFUN([PKG_CHECK_MODULES],
  [AC_REQUIRE([PKG_PROG_PKG_CONFIG])dnl
  AC_ARG_VAR([$1][_CFLAGS], [C compiler flags for $1, overriding pkg-config])dnl
  AC_ARG_VAR([$1][_LIBS], [linker flags for $1, overriding pkg-config])dnl
  
  pkg_failed=no
  AC_MSG_CHECKING([for $1])
  
  _PKG_CONFIG([$1][_CFLAGS], [cflags], [$2])
  _PKG_CONFIG([$1][_LIBS], [libs], [$2])
  
  m4_define([_PKG_TEXT], [Alternatively, you may set the environment variables $1[]_CFLAGS
  and $1[]_LIBS to avoid the need to call pkg-config.
  See the pkg-config man page for more details.])
  
  if test $pkg_failed = yes; then
          _PKG_SHORT_ERRORS_SUPPORTED
          if test $_pkg_short_errors_supported = yes; then
  	        $1[]_PKG_ERRORS=`$PKG_CONFIG --short-errors --errors-to-stdout --print-errors "$2"`
          else
  	        $1[]_PKG_ERRORS=`$PKG_CONFIG --errors-to-stdout --print-errors "$2"`
          fi
  	# Put the nasty error message in config.log where it belongs
  	echo "$$1[]_PKG_ERRORS" >&AS_MESSAGE_LOG_FD
  
  	ifelse([$4], , [AC_MSG_ERROR(dnl
  [Package requirements ($2) were not met:
  
  $$1_PKG_ERRORS
  
  Consider adjusting the PKG_CONFIG_PATH environment variable if you
  installed software in a non-standard prefix.
  
  _PKG_TEXT
  ])],
  		[AC_MSG_RESULT([no])
                  $4])
  elif test $pkg_failed = untried; then
  	ifelse([$4], , [AC_MSG_FAILURE(dnl
  [The pkg-config script could not be found or is too old.  Make sure it
  is in your PATH or set the PKG_CONFIG environment variable to the full
  path to pkg-config.
  
  _PKG_TEXT
  
  To get pkg-config, see <http://pkg-config.freedesktop.org/>.])],
  		[$4])
  else
  	$1[]_CFLAGS=$pkg_cv_[]$1[]_CFLAGS
  	$1[]_LIBS=$pkg_cv_[]$1[]_LIBS
          AC_MSG_RESULT([yes])
  	ifelse([$3], , :, [$3])
  fi[]dnl
  ])# PKG_CHECK_MODULES
  