[gimp/gtk3-port: 199/228] configure.ac: use the new GTK_CHECK_BACKEND() macro

[Michael Natterer <mitch src gnome org>]

commit e5b7c8131a073b4869fa88b65bea4874a1c42068
Author: Michael Natterer <mitch gimp org>
Date:   Wed Feb 16 20:49:33 2011 +0100

    configure.ac: use the new GTK_CHECK_BACKEND() macro
    
    so GTK+ target detection works again.

 configure.ac |    9 +++++----
 1 files changed, 5 insertions(+), 4 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 898bf6c..b1221ea 100644
--- a/configure.ac
+++ b/configure.ac
@@ -954,11 +954,12 @@ fi
 ################################
 
 # Check if building for GTK+-X11
-gdk_target=`$PKG_CONFIG --variable=target gtk+-3.0`
+GTK_CHECK_BACKEND([x11], [gtk_required_version],
+                  [have_gtk_x11=yes], [have_gtk_x11=no])
 
-have_libxmu="no (building for $gdk_target)"
+have_libxmu="no (building for `pkg-config --variable=targets gtk-3.0`)"
 
-if test "$gdk_target" = x11; then
+if test "x$have_gtk_x11" = "xyes"; then
 
    # doc-shooter is X11 specific
    DOC_SHOOTER=doc-shooter
@@ -1302,7 +1303,7 @@ gimp_save_CFLAGS="$CFLAGS"
 CFLAGS="$CFLAGS $X_CFLAGS"
 gimp_save_LDFLAGS="$LDFLAGS"
 LDFLAGS="$LDFLAGS $X_LIBS"
-if test "$gdk_target" = x11; then
+if test "x$have_gtk_x11" = "xyes"; then
   lib_X11=-lX11
 fi
 have_libxpm=no