[libwnck] xutils: Correctly link against libXrender

[Marco Trevisan <marcotrevi src gnome org>]

commit eddfee28c623fd7f4a0b6e38373798f96121e445
Author: David King <amigadave amigadave com>
Date:   Mon Oct 13 13:38:24 2014 +0100

    xutils: Correctly link against libXrender
    
    If using cairo-xlib-xrender functions (and especially XRender
    functions), use the libraries from the cairo-xlib-xrender pkg-config
    file explicitly rather than relying on implicit linking. Avoids linker
    errors regarding an undefined reference to XRenderFindStandardFormat.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=738455

 configure.ac     |    6 ++++++
 libwnck/xutils.c |    4 ++--
 2 files changed, 8 insertions(+), 2 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 5fe3b21..d0684ad 100644
--- a/configure.ac
+++ b/configure.ac
@@ -121,6 +121,11 @@ PKG_CHECK_MODULES(XLIB, x11,
      fi])
 AC_SUBST(X11_PACKAGE)
 
+PKG_CHECK_EXISTS([cairo-xlib-xrender],
+                 [AC_DEFINE_UNQUOTED([HAVE_CAIRO_XLIB_XRENDER], [1],
+                                     [Define if building against cairo-xlib-xrender])
+                  CAIRO_XLIB_XRENDER_PACKAGE=cairo-xlib-xrender])
+
 AC_MSG_CHECKING([if building with X Resource Information Extension Library])
 if $PKG_CONFIG xres; then
   AC_MSG_RESULT([yes])
@@ -146,6 +151,7 @@ PKG_CHECK_MODULES([LIBWNCK],[
        gtk+-3.0 >= 3.4
        glib-2.0 >= 2.32
        gobject-2.0 >= 2.13.0
+       $CAIRO_XLIB_XRENDER_PACKAGE
        $STARTUP_NOTIFICATION_PACKAGE
        $XRES_PACKAGE
 ])
diff --git a/libwnck/xutils.c b/libwnck/xutils.c
index 53f3083..02ce741 100644
--- a/libwnck/xutils.c
+++ b/libwnck/xutils.c
@@ -24,7 +24,7 @@
 #include <string.h>
 #include <stdio.h>
 #include <cairo-xlib.h>
-#if CAIRO_HAS_XLIB_XRENDER_SURFACE
+#if HAVE_CAIRO_XLIB_XRENDER
 #include <cairo-xlib-xrender.h>
 #endif
 #include "screen.h"
@@ -1718,7 +1718,7 @@ _wnck_cairo_surface_get_from_pixmap (Screen *screen,
        }
       else
        {
-#if CAIRO_HAS_XLIB_XRENDER_SURFACE
+#if HAVE_CAIRO_XLIB_XRENDER
          int std;
 
          switch (depth_ret) {