libgtk3: wayland backend requires headers >= 3.17

As pointed by Thomas, fixes:
http://autobuild.buildroot.org/results/473/473fb2f416311ee8a8a8719e3fb3689d9226f451/

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/libgtk3/Config.in

@@ -58,13 +58,15 @@ config BR2_PACKAGE_LIBGTK3_BROADWAY
 	  Then open a web browser at address http://192.168.0.1:8080.
 	  Javascript and web sockets should be enabled.
 
-comment "Wayland GDK backend needs an OpenGL EGL backend provided by mesa3d"
-	depends on !BR2_PACKAGE_MESA3D_OPENGL_EGL
+comment "Wayland GDK backend needs an OpenGL EGL backend provided by mesa3d w/ headers >= 3.17"
+	depends on !BR2_PACKAGE_MESA3D_OPENGL_EGL || \
+		!BR2_TOOLCHAIN_HEADERS_AT_LEAST_3_17
 
 config BR2_PACKAGE_LIBGTK3_WAYLAND
 	bool "Wayland GDK backend"
 	default y
 	depends on BR2_PACKAGE_MESA3D_OPENGL_EGL
+	depends on BR2_TOOLCHAIN_HEADERS_AT_LEAST_3_17
 	select BR2_PACKAGE_WAYLAND
 	select BR2_PACKAGE_WAYLAND_PROTOCOLS
 	select BR2_PACKAGE_LIBXKBCOMMON