5 files changed, 491 insertions, 71 deletions

diff --git a/bootstrap b/bootstrap
index e219832..435da14 100755
--- a/bootstrap
+++ b/bootstrap
@@ -1,7 +1,3 @@
 #!/bin/sh
 rm -rf libltdl
-libtoolize --force
-aclocal
-autoheader
-automake --force-missing --add-missing
 autoreconf -if
diff --git a/compile b/compile
index a81e000..862a14e 100755
--- a/compile
+++ b/compile
@@ -1,9 +1,10 @@
 #! /bin/sh
-# Wrapper for compilers which do not understand `-c -o'.
+# Wrapper for compilers which do not understand '-c -o'.
 
-scriptversion=2003-11-09.00
+scriptversion=2012-03-05.13; # UTC
 
-# Copyright (C) 1999, 2000, 2003 Free Software Foundation, Inc.
+# Copyright (C) 1999, 2000, 2003, 2004, 2005, 2009, 2010, 2012 Free
+# Software Foundation, Inc.
 # Written by Tom Tromey <tromey@cygnus.com>.
 #
 # This program is free software; you can redistribute it and/or modify
@@ -17,8 +18,7 @@ scriptversion=2003-11-09.00
 # 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.
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # As a special exception to the GNU General Public License, if you
 # distribute this file as part of a program that contains a
@@ -29,102 +29,308 @@ scriptversion=2003-11-09.00
 # bugs to <bug-automake@gnu.org> or send patches to
 # <automake-patches@gnu.org>.
 
+nl='
+'
+
+# We need space, tab and new line, in precisely that order.  Quoting is
+# there to prevent tools from complaining about whitespace usage.
+IFS=" ""        $nl"
+
+file_conv=
+
+# func_file_conv build_file lazy
+# Convert a $build file to $host form and store it in $file
+# Currently only supports Windows hosts. If the determined conversion
+# type is listed in (the comma separated) LAZY, no conversion will
+# take place.
+func_file_conv ()
+{
+  file=$1
+  case $file in
+    / | /[!/]*) # absolute file, and not a UNC file
+      if test -z "$file_conv"; then
+        # lazily determine how to convert abs files
+        case `uname -s` in
+          MINGW*)
+            file_conv=mingw
+            ;;
+          CYGWIN*)
+            file_conv=cygwin
+            ;;
+          *)
+            file_conv=wine
+            ;;
+        esac
+      fi
+      case $file_conv/,$2, in
+        *,$file_conv,*)
+          ;;
+        mingw/*)
+          file=`cmd //C echo "$file " | sed -e 's/"\(.*\) " *$/\1/'`
+          ;;
+        cygwin/*)
+          file=`cygpath -m "$file" || echo "$file"`
+          ;;
+        wine/*)
+          file=`winepath -w "$file" || echo "$file"`
+          ;;
+      esac
+      ;;
+  esac
+}
+
+# func_cl_dashL linkdir
+# Make cl look for libraries in LINKDIR
+func_cl_dashL ()
+{
+  func_file_conv "$1"
+  if test -z "$lib_path"; then
+    lib_path=$file
+  else
+    lib_path="$lib_path;$file"
+  fi
+  linker_opts="$linker_opts -LIBPATH:$file"
+}
+
+# func_cl_dashl library
+# Do a library search-path lookup for cl
+func_cl_dashl ()
+{
+  lib=$1
+  found=no
+  save_IFS=$IFS
+  IFS=';'
+  for dir in $lib_path $LIB
+  do
+    IFS=$save_IFS
+    if $shared && test -f "$dir/$lib.dll.lib"; then
+      found=yes
+      lib=$dir/$lib.dll.lib
+      break
+    fi
+    if test -f "$dir/$lib.lib"; then
+      found=yes
+      lib=$dir/$lib.lib
+      break
+    fi
+  done
+  IFS=$save_IFS
+
+  if test "$found" != yes; then
+    lib=$lib.lib
+  fi
+}
+
+# func_cl_wrapper cl arg...
+# Adjust compile command to suit cl
+func_cl_wrapper ()
+{
+  # Assume a capable shell
+  lib_path=
+  shared=:
+  linker_opts=
+  for arg
+  do
+    if test -n "$eat"; then
+      eat=
+    else
+      case $1 in
+        -o)
+          # configure might choose to run compile as 'compile cc -o foo foo.c'.
+          eat=1
+          case $2 in
+            *.o | *.[oO][bB][jJ])
+              func_file_conv "$2"
+              set x "$@" -Fo"$file"
+              shift
+              ;;
+            *)
+              func_file_conv "$2"
+              set x "$@" -Fe"$file"
+              shift
+              ;;
+          esac
+          ;;
+        -I)
+          eat=1
+          func_file_conv "$2" mingw
+          set x "$@" -I"$file"
+          shift
+          ;;
+        -I*)
+          func_file_conv "${1#-I}" mingw
+          set x "$@" -I"$file"
+          shift
+          ;;
+        -l)
+          eat=1
+          func_cl_dashl "$2"
+          set x "$@" "$lib"
+          shift
+          ;;
+        -l*)
+          func_cl_dashl "${1#-l}"
+          set x "$@" "$lib"
+          shift
+          ;;
+        -L)
+          eat=1
+          func_cl_dashL "$2"
+          ;;
+        -L*)
+          func_cl_dashL "${1#-L}"
+          ;;
+        -static)
+          shared=false
+          ;;
+        -Wl,*)
+          arg=${1#-Wl,}
+          save_ifs="$IFS"; IFS=','
+          for flag in $arg; do
+            IFS="$save_ifs"
+            linker_opts="$linker_opts $flag"
+          done
+          IFS="$save_ifs"
+          ;;
+        -Xlinker)
+          eat=1
+          linker_opts="$linker_opts $2"
+          ;;
+        -*)
+          set x "$@" "$1"
+          shift
+          ;;
+        *.cc | *.CC | *.cxx | *.CXX | *.[cC]++)
+          func_file_conv "$1"
+          set x "$@" -Tp"$file"
+          shift
+          ;;
+        *.c | *.cpp | *.CPP | *.lib | *.LIB | *.Lib | *.OBJ | *.obj | *.[oO])
+          func_file_conv "$1" mingw
+          set x "$@" "$file"
+          shift
+          ;;
+        *)
+          set x "$@" "$1"
+          shift
+          ;;
+      esac
+    fi
+    shift
+  done
+  if test -n "$linker_opts"; then
+    linker_opts="-link$linker_opts"
+  fi
+  exec "$@" $linker_opts
+  exit 1
+}
+
+eat=
+
 case $1 in
   '')
-     echo "$0: No command.  Try \`$0 --help' for more information." 1>&2
+     echo "$0: No command.  Try '$0 --help' for more information." 1>&2
      exit 1;
      ;;
   -h | --h*)
     cat <<\EOF
 Usage: compile [--help] [--version] PROGRAM [ARGS]
 
-Wrapper for compilers which do not understand `-c -o'.
-Remove `-o dest.o' from ARGS, run PROGRAM with the remaining
+Wrapper for compilers which do not understand '-c -o'.
+Remove '-o dest.o' from ARGS, run PROGRAM with the remaining
 arguments, and rename the output as expected.
 
 If you are trying to build a whole package this is not the
-right script to run: please start by reading the file `INSTALL'.
+right script to run: please start by reading the file 'INSTALL'.
 
 Report bugs to <bug-automake@gnu.org>.
 EOF
-    exit 0
+    exit $?
     ;;
   -v | --v*)
     echo "compile $scriptversion"
-    exit 0
+    exit $?
+    ;;
+  cl | *[/\\]cl | cl.exe | *[/\\]cl.exe )
+    func_cl_wrapper "$@"      # Doesn't return...
     ;;
 esac
 
-
-prog=$1
-shift
-
 ofile=
 cfile=
-args=
-while test $# -gt 0; do
-  case "$1" in
-    -o)
-      # configure might choose to run compile as `compile cc -o foo foo.c'.
-      # So we do something ugly here.
-      ofile=$2
-      shift
-      case "$ofile" in
-        *.o | *.obj)
-          ;;
-        *)
-          args="$args -o $ofile"
-          ofile=
-          ;;
-      esac
-       ;;
-    *.c)
-      cfile=$1
-      args="$args $1"
-      ;;
-    *)
-      args="$args $1"
-      ;;
-  esac
+
+for arg
+do
+  if test -n "$eat"; then
+    eat=
+  else
+    case $1 in
+      -o)
+        # configure might choose to run compile as 'compile cc -o foo foo.c'.
+        # So we strip '-o arg' only if arg is an object.
+        eat=1
+        case $2 in
+          *.o | *.obj)
+            ofile=$2
+            ;;
+          *)
+            set x "$@" -o "$2"
+            shift
+            ;;
+        esac
+        ;;
+      *.c)
+        cfile=$1
+        set x "$@" "$1"
+        shift
+        ;;
+      *)
+        set x "$@" "$1"
+        shift
+        ;;
+    esac
+  fi
   shift
 done
 
 if test -z "$ofile" || test -z "$cfile"; then
-  # If no `-o' option was seen then we might have been invoked from a
+  # If no '-o' option was seen then we might have been invoked from a
   # pattern rule where we don't need one.  That is ok -- this is a
   # normal compilation that the losing compiler can handle.  If no
-  # `.c' file was seen then we are probably linking.  That is also
+  # '.c' file was seen then we are probably linking.  That is also
   # ok.
-  exec "$prog" $args
+  exec "$@"
 fi
 
 # Name of file we expect compiler to create.
-cofile=`echo $cfile | sed -e 's|^.*/||' -e 's/\.c$/.o/'`
+cofile=`echo "$cfile" | sed 's|^.*[\\/]||; s|^[a-zA-Z]:||; s/\.c$/.o/'`
 
 # Create the lock directory.
-# Note: use `[/.-]' here to ensure that we don't use the same name
+# Note: use '[/\\:.-]' here to ensure that we don't use the same name
 # that we are using for the .o file.  Also, base the name on the expected
 # object file name, since that is what matters with a parallel build.
-lockdir=`echo $cofile | sed -e 's|[/.-]|_|g'`.d
+lockdir=`echo "$cofile" | sed -e 's|[/\\:.-]|_|g'`.d
 while true; do
-  if mkdir $lockdir > /dev/null 2>&1; then
+  if mkdir "$lockdir" >/dev/null 2>&1; then
     break
   fi
   sleep 1
 done
 # FIXME: race condition here if user kills between mkdir and trap.
-trap "rmdir $lockdir; exit 1" 1 2 15
+trap "rmdir '$lockdir'; exit 1" 1 2 15
 
 # Run the compile.
-"$prog" $args
-status=$?
+"$@"
+ret=$?
 
 if test -f "$cofile"; then
-  mv "$cofile" "$ofile"
+  test "$cofile" = "$ofile" || mv "$cofile" "$ofile"
+elif test -f "${cofile}bj"; then
+  test "${cofile}bj" = "$ofile" || mv "${cofile}bj" "$ofile"
 fi
 
-rmdir $lockdir
-exit $status
+rmdir "$lockdir"
+exit $ret
 
 # Local Variables:
 # mode: shell-script
@@ -132,5 +338,6 @@ exit $status
 # eval: (add-hook 'write-file-hooks 'time-stamp)
 # time-stamp-start: "scriptversion="
 # time-stamp-format: "%:y-%02m-%02d.%02H"
-# time-stamp-end: "$"
+# time-stamp-time-zone: "UTC"
+# time-stamp-end: "; # UTC"
 # End:
diff --git a/configure.ac b/configure.ac
index 17647a9..ab6fe98 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2,6 +2,7 @@
 AC_PREREQ(2.61)
 AC_INIT([libextractor], [0.7.0], [bug-libextractor@gnu.org])
 AC_CONFIG_HEADERS([config.h])
+AC_CONFIG_MACRO_DIR([m4])
 AH_TOP([#define _GNU_SOURCE  1])
 AC_CANONICAL_TARGET
 AC_CANONICAL_HOST
@@ -14,8 +15,6 @@ AC_SUBST(LIB_VERSION_CURRENT)
 AC_SUBST(LIB_VERSION_REVISION)
 AC_SUBST(LIB_VERSION_AGE)
 
-LT_CONFIG_LTDL_DIR([libltdl])
-AC_CONFIG_AUX_DIR([libltdl/config])
 AM_INIT_AUTOMAKE([silent-rules])
 
 # Checks for programs.
@@ -30,6 +29,8 @@ AC_PROG_INSTALL
 AC_PROG_LN_S
 AC_PROG_MAKE_SET
 AC_CANONICAL_HOST
+AC_LIBLTDL_CONVENIENCE
+AC_PROG_LIBTOOL
 # save LIBS, libtool does a AC_SEARCH_LIBS(dlopen, dl), but plugins
 # need not have -ldl added
 LIBSOLD=$LIBS
@@ -530,7 +531,6 @@ AC_CHECK_LIB(gsf-1, gsf_init, AC_DEFINE(HAVE_GSF_INIT,1,[gsf_init supported]))
 AC_CHECK_PROG([HAVE_ZZUF],[zzuf], 1, 0)
 AM_CONDITIONAL(HAVE_ZZUF, test 0 != $HAVE_ZZUF)
 
-ffmpeg_enabled=0
 AC_MSG_CHECKING([whether to enable the FFmpeg thumbnail extractor])
 AC_ARG_ENABLE(ffmpeg,
  [AC_HELP_STRING([--enable-ffmpeg],[Enable FFmpeg support])
@@ -543,16 +543,16 @@ AC_ARG_ENABLE(ffmpeg,
         ffmpeg_enabled=1
         ;;
   esac],
-  [     AC_MSG_RESULT(no)
-        ffmpeg_enabled=0])
-AM_CONDITIONAL(HAVE_FFMPEG, test x$ffmpeg_enabled != x0)
+  [     AC_MSG_RESULT(yes)
+        ffmpeg_enabled=1])
 if test x$ffmpeg_enabled = x1
 then
-  AC_CHECK_HEADERS(libavutil/avutil.h ffmpeg/avutil.h)
-  AC_CHECK_HEADERS(libavformat/avformat.h ffmpeg/avformat.h)
-  AC_CHECK_HEADERS(libavcodec/avcodec.h ffmpeg/avcodec.h)
-  AC_CHECK_HEADERS(libswscale/swscale.h ffmpeg/swscale.h)
+  ffmpeg_enabled=0
+  AC_CHECK_LIB(swscale, sws_getContext,
+    ffmpeg_enabled=1)
+  AC_CHECK_HEADERS([libavutil/avutil.h ffmpeg/avutil.h libavformat/avformat.h ffmpeg/avformat.h libavcodec/avcodec.h ffmpeg/avcodec.h libswscale/swscale.h ffmpeg/swscale.h])
 fi
+AM_CONDITIONAL(HAVE_FFMPEG, test x$ffmpeg_enabled != x0)
 
 
 LE_INTLINCL=""
@@ -658,8 +658,6 @@ fi
 if test "x$ffmpeg_enabled" = "x0"
 then
  AC_MSG_NOTICE([NOTICE: FFmpeg thumbnailer plugin disabled])
-else 
- AC_MSG_NOTICE([NOTICE: FFmpeg thumbnailer plugin enabled (security untested)])
 fi
 
 if test "x$without_gtk" = "xtrue" 
diff --git a/doc/version.texi b/doc/version.texi
index b7f4560..b3e6e4c 100644
--- a/doc/version.texi
+++ b/doc/version.texi
@@ -1,4 +1,4 @@
-@set UPDATED 26 August 2012
+@set UPDATED 28 August 2012
 @set UPDATED-MONTH August 2012
 @set EDITION 0.7.0
 @set VERSION 0.7.0
diff --git a/m4/gtk-3.0.m4 b/m4/gtk-3.0.m4
new file mode 100644
index 0000000..5238b43
--- /dev/null
+++ b/m4/gtk-3.0.m4
@@ -0,0 +1,219 @@
+# Configure paths for GTK+
+# Owen Taylor     1997-2001
+
+dnl AM_PATH_GTK_3_0([MINIMUM-VERSION, [ACTION-IF-FOUND [, ACTION-IF-NOT-FOUND [, MODULES]]]])
+dnl Test for GTK+, and define GTK_CFLAGS and GTK_LIBS, if gthread is specified in MODULES, 
+dnl pass to pkg-config
+dnl
+AC_DEFUN([AM_PATH_GTK_3_0],
+[dnl 
+dnl Get the cflags and libraries from pkg-config
+dnl
+AC_ARG_ENABLE(gtktest, [  --disable-gtktest       do not try to compile and run a test GTK+ program],
+                    , enable_gtktest=yes)
+
+  pkg_config_args=gtk+-3.0
+  for module in . $4
+  do
+      case "$module" in
+         gthread)
+             pkg_config_args="$pkg_config_args gthread-2.0"
+         ;;
+      esac
+  done
+
+  no_gtk=""
+
+  AC_PATH_PROG(PKG_CONFIG, pkg-config, no)
+
+  if test x$PKG_CONFIG != xno ; then
+    if $PKG_CONFIG --atleast-pkgconfig-version 0.7 ; then
+      :
+    else
+      echo "*** pkg-config too old; version 0.7 or better required."
+      no_gtk=yes
+      PKG_CONFIG=no
+    fi
+  else
+    no_gtk=yes
+  fi
+
+  min_gtk_version=ifelse([$1], ,3.0.0,$1)
+  AC_MSG_CHECKING(for GTK+ - version >= $min_gtk_version)
+
+  if test x$PKG_CONFIG != xno ; then
+    ## don't try to run the test against uninstalled libtool libs
+    if $PKG_CONFIG --uninstalled $pkg_config_args; then
+          echo "Will use uninstalled version of GTK+ found in PKG_CONFIG_PATH"
+          enable_gtktest=no
+    fi
+
+    if $PKG_CONFIG --atleast-version $min_gtk_version $pkg_config_args; then
+          :
+    else
+          no_gtk=yes
+    fi
+  fi
+
+  if test x"$no_gtk" = x ; then
+    GTK_CFLAGS=`$PKG_CONFIG $pkg_config_args --cflags`
+    GTK_LIBS=`$PKG_CONFIG $pkg_config_args --libs`
+    gtk_config_major_version=`$PKG_CONFIG --modversion gtk+-3.0 | \
+           sed 's/\([[0-9]]*\).\([[0-9]]*\).\([[0-9]]*\)/\1/'`
+    gtk_config_minor_version=`$PKG_CONFIG --modversion gtk+-3.0 | \
+           sed 's/\([[0-9]]*\).\([[0-9]]*\).\([[0-9]]*\)/\2/'`
+    gtk_config_micro_version=`$PKG_CONFIG --modversion gtk+-3.0 | \
+           sed 's/\([[0-9]]*\).\([[0-9]]*\).\([[0-9]]*\)/\3/'`
+    if test "x$enable_gtktest" = "xyes" ; then
+      ac_save_CFLAGS="$CFLAGS"
+      ac_save_LIBS="$LIBS"
+      CFLAGS="$CFLAGS $GTK_CFLAGS"
+      LIBS="$GTK_LIBS $LIBS"
+dnl
+dnl Now check if the installed GTK+ is sufficiently new. (Also sanity
+dnl checks the results of pkg-config to some extent)
+dnl
+      rm -f conf.gtktest
+      AC_TRY_RUN([
+#include <gtk/gtk.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+int 
+main ()
+{
+  int major, minor, micro;
+  char *tmp_version;
+
+  fclose (fopen ("conf.gtktest", "w"));
+
+  /* HP/UX 9 (%@#!) writes to sscanf strings */
+  tmp_version = g_strdup("$min_gtk_version");
+  if (sscanf(tmp_version, "%d.%d.%d", &major, &minor, &micro) != 3) {
+     printf("%s, bad version string\n", "$min_gtk_version");
+     exit(1);
+   }
+
+  if ((gtk_major_version != $gtk_config_major_version) ||
+      (gtk_minor_version != $gtk_config_minor_version) ||
+      (gtk_micro_version != $gtk_config_micro_version))
+    {
+      printf("\n*** 'pkg-config --modversion gtk+-3.0' returned %d.%d.%d, but GTK+ (%d.%d.%d)\n", 
+             $gtk_config_major_version, $gtk_config_minor_version, $gtk_config_micro_version,
+             gtk_major_version, gtk_minor_version, gtk_micro_version);
+      printf ("*** was found! If pkg-config was correct, then it is best\n");
+      printf ("*** to remove the old version of GTK+. You may also be able to fix the error\n");
+      printf("*** by modifying your LD_LIBRARY_PATH enviroment variable, or by editing\n");
+      printf("*** /etc/ld.so.conf. Make sure you have run ldconfig if that is\n");
+      printf("*** required on your system.\n");
+      printf("*** If pkg-config was wrong, set the environment variable PKG_CONFIG_PATH\n");
+      printf("*** to point to the correct configuration files\n");
+    } 
+  else if ((gtk_major_version != GTK_MAJOR_VERSION) ||
+           (gtk_minor_version != GTK_MINOR_VERSION) ||
+           (gtk_micro_version != GTK_MICRO_VERSION))
+    {
+      printf("*** GTK+ header files (version %d.%d.%d) do not match\n",
+             GTK_MAJOR_VERSION, GTK_MINOR_VERSION, GTK_MICRO_VERSION);
+      printf("*** library (version %d.%d.%d)\n",
+             gtk_major_version, gtk_minor_version, gtk_micro_version);
+    }
+  else
+    {
+      if ((gtk_major_version > major) ||
+        ((gtk_major_version == major) && (gtk_minor_version > minor)) ||
+        ((gtk_major_version == major) && (gtk_minor_version == minor) && (gtk_micro_version >= micro)))
+      {
+        return 0;
+       }
+     else
+      {
+        printf("\n*** An old version of GTK+ (%d.%d.%d) was found.\n",
+               gtk_major_version, gtk_minor_version, gtk_micro_version);
+        printf("*** You need a version of GTK+ newer than %d.%d.%d. The latest version of\n",
+               major, minor, micro);
+        printf("*** GTK+ is always available from ftp://ftp.gtk.org.\n");
+        printf("***\n");
+        printf("*** If you have already installed a sufficiently new version, this error\n");
+        printf("*** probably means that the wrong copy of the pkg-config shell script is\n");
+        printf("*** being found. The easiest way to fix this is to remove the old version\n");
+        printf("*** of GTK+, but you can also set the PKG_CONFIG environment to point to the\n");
+        printf("*** correct copy of pkg-config. (In this case, you will have to\n");
+        printf("*** modify your LD_LIBRARY_PATH enviroment variable, or edit /etc/ld.so.conf\n");
+        printf("*** so that the correct libraries are found at run-time))\n");
+      }
+    }
+  return 1;
+}
+],, no_gtk=yes,[echo $ac_n "cross compiling; assumed OK... $ac_c"])
+       CFLAGS="$ac_save_CFLAGS"
+       LIBS="$ac_save_LIBS"
+     fi
+  fi
+  if test "x$no_gtk" = x ; then
+     AC_MSG_RESULT(yes (version $gtk_config_major_version.$gtk_config_minor_version.$gtk_config_micro_version))
+     ifelse([$2], , :, [$2])
+  else
+     AC_MSG_RESULT(no)
+     if test "$PKG_CONFIG" = "no" ; then
+       echo "*** A new enough version of pkg-config was not found."
+       echo "*** See http://pkgconfig.sourceforge.net"
+     else
+       if test -f conf.gtktest ; then
+        :
+       else
+          echo "*** Could not run GTK+ test program, checking why..."
+          ac_save_CFLAGS="$CFLAGS"
+          ac_save_LIBS="$LIBS"
+          CFLAGS="$CFLAGS $GTK_CFLAGS"
+          LIBS="$LIBS $GTK_LIBS"
+          AC_TRY_LINK([
+#include <gtk/gtk.h>
+#include <stdio.h>
+],      [ return ((gtk_major_version) || (gtk_minor_version) || (gtk_micro_version)); ],
+        [ echo "*** The test program compiled, but did not run. This usually means"
+          echo "*** that the run-time linker is not finding GTK+ or finding the wrong"
+          echo "*** version of GTK+. If it is not finding GTK+, you'll need to set your"
+          echo "*** LD_LIBRARY_PATH environment variable, or edit /etc/ld.so.conf to point"
+          echo "*** to the installed location  Also, make sure you have run ldconfig if that"
+          echo "*** is required on your system"
+          echo "***"
+          echo "*** If you have an old version installed, it is best to remove it, although"
+          echo "*** you may also be able to get things to work by modifying LD_LIBRARY_PATH" ],
+        [ echo "*** The test program failed to compile or link. See the file config.log for the"
+          echo "*** exact error that occured. This usually means GTK+ is incorrectly installed."])
+          CFLAGS="$ac_save_CFLAGS"
+          LIBS="$ac_save_LIBS"
+       fi
+     fi
+     GTK_CFLAGS=""
+     GTK_LIBS=""
+     ifelse([$3], , :, [$3])
+  fi
+  AC_SUBST(GTK_CFLAGS)
+  AC_SUBST(GTK_LIBS)
+  rm -f conf.gtktest
+])
+
+dnl GTK_CHECK_BACKEND(BACKEND-NAME [, MINIMUM-VERSION [, ACTION-IF-FOUND [, ACTION-IF-NOT-FOUND]]])
+dnl   Tests for BACKEND-NAME in the GTK targets list
+dnl
+AC_DEFUN([GTK_CHECK_BACKEND],
+[
+  pkg_config_args=ifelse([$1],,gtk+-3.0, gtk+-$1-3.0)
+  min_gtk_version=ifelse([$2],,3.0.0,$2)
+
+  AC_PATH_PROG(PKG_CONFIG, [pkg-config], [AC_MSG_ERROR([No pkg-config found])])
+
+  if $PKG_CONFIG --atleast-version $min_gtk_version $pkg_config_args ; then
+    target_found=yes
+  else
+    target_found=no
+  fi
+
+  if test "x$target_found" = "xno"; then
+    ifelse([$4],,[AC_MSG_ERROR([Backend $backend not found.])],[$4])
+  else
+    ifelse([$3],,[:],[$3])
+  fi
+])