[gtksourceview] Bug 618242 - Build with gtk+-3.0 if it's available

[Jesse van den Kieboom <jessevdk src gnome org>]

commit 453129ab4fe6261459cac06f7ba1ba07f248ea60
Author: Garrett Regier <alias301 gmail com>
Date:   Mon May 10 02:35:02 2010 -0700

    Bug 618242 - Build with gtk+-3.0 if it's available

 configure.ac |   15 ++++++++++++---
 1 files changed, 12 insertions(+), 3 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 6f3daf0..c90f5ab 100644
--- a/configure.ac
+++ b/configure.ac
@@ -30,7 +30,8 @@ LT_INIT([disable-static])
 AC_CHECK_HEADERS([unistd.h])
 
 # Dependencies
-GTK_REQUIRED_VERSION=2.12.0
+GTK_REQUIRED=
+GTK_REQUIRED_VERSION=
 LIBXML_REQUIRED_VERSION=2.5.0
 GLADE_UI_REQUIRED=3.2
 
@@ -45,13 +46,21 @@ AC_PATH_PROG(GLIB_MKENUMS, glib-mkenums)
 GNOME_COMPILE_WARNINGS([maximum])
 #GNOME_MAINTAINER_MODE_DEFINES
 
+PKG_CHECK_EXISTS([gtk+-3.0 >= 2.90],
+		 [
+		 	GTK_REQUIRED=gtk+-3.0
+		 	GTK_REQUIRED_VERSION=2.90.0
+		 ],[
+		 	GTK_REQUIRED=gtk+-2.0
+		 	GTK_REQUIRED_VERSION=2.12.0
+		 ])
+
 PKG_CHECK_MODULES(DEP, [
 	gio-2.0
-	gtk+-2.0 >= $GTK_REQUIRED_VERSION
+	$GTK_REQUIRED >= $GTK_REQUIRED_VERSION
 	libxml-2.0 >= $LIBXML_REQUIRED_VERSION
 ])
 
-
 dnl Check to enable completion providers
 AC_ARG_ENABLE(providers,
 	    AS_HELP_STRING([--enable-completion-providers],