[mutter] backends/x11: add a flag to denote randr 1.5 is in use.

[Jasper St. Pierre <jstpierre src gnome org>]

commit ef296031cbf0883135b7a1f436c6a69f75122efe
Author: Dave Airlie <airlied redhat com>
Date:   Tue Mar 31 10:38:44 2015 +1000

    backends/x11: add a flag to denote randr 1.5 is in use.
    
    If the server reports randr 1.5, just cache the information
    for later patches to use.

 configure.ac                                   |    2 ++
 src/backends/x11/meta-monitor-manager-xrandr.c |   12 ++++++++++++
 2 files changed, 14 insertions(+), 0 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 7cb832b..88d162a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -284,6 +284,8 @@ AC_CHECK_LIB(Xrandr, XRRUpdateConfiguration,
 
 if test "x$found_randr" = "xyes"; then
    AC_DEFINE(HAVE_RANDR, , [Have the Xrandr extension library])
+   PKG_CHECK_EXISTS([xrandr >= 1.5.0],
+                 AC_DEFINE([HAVE_XRANDR15],[1],[Define if you have support for XRandR 1.5 or greater]))
 fi
 
 MUTTER_LIBS="$MUTTER_LIBS $RANDR_LIBS $X_LIBS $X_PRE_LIBS -lX11 $X_EXTRA_LIBS -lm"
diff --git a/src/backends/x11/meta-monitor-manager-xrandr.c b/src/backends/x11/meta-monitor-manager-xrandr.c
index 70bef2e..bbccce9 100644
--- a/src/backends/x11/meta-monitor-manager-xrandr.c
+++ b/src/backends/x11/meta-monitor-manager-xrandr.c
@@ -58,6 +58,7 @@ struct _MetaMonitorManagerXrandr
   XRRScreenResources *resources;
   int rr_event_base;
   int rr_error_base;
+  gboolean has_randr15;
 };
 
 struct _MetaMonitorManagerXrandrClass
@@ -1228,6 +1229,7 @@ meta_monitor_manager_xrandr_init (MetaMonitorManagerXrandr *manager_xrandr)
     }
   else
     {
+      int major_version, minor_version;
       /* We only use ScreenChangeNotify, but GDK uses the others,
         and we don't want to step on its toes */
       XRRSelectInput (manager_xrandr->xdisplay,
@@ -1235,6 +1237,16 @@ meta_monitor_manager_xrandr_init (MetaMonitorManagerXrandr *manager_xrandr)
                      RRScreenChangeNotifyMask
                      | RRCrtcChangeNotifyMask
                      | RROutputPropertyNotifyMask);
+
+      manager_xrandr->has_randr15 = FALSE;
+      XRRQueryVersion (manager_xrandr->xdisplay, &major_version,
+                       &minor_version);
+#ifdef HAVE_XRANDR15
+      if (major_version > 1 ||
+          (major_version == 1 &&
+           minor_version >= 5))
+        manager_xrandr->has_randr15 = TRUE;
+#endif
     }
 }