package/x11r7/xserver_xorg-server: Glamor depends on dri3

Fixes

../../../glamor/glamor_egl.c:603:25: error: unknown type name 'RRProviderPtr'
                         RRProviderPtr provider,
                         ^
../../../glamor/glamor_egl.c:650:1: error: unknown type name 'dri3_screen_info_rec'
 static dri3_screen_info_rec glamor_dri3_info = {
 ^

using this defconfig

BR2_TOOLCHAIN_BUILDROOT_LARGEFILE=y
BR2_TOOLCHAIN_BUILDROOT_WCHAR=y
BR2_TOOLCHAIN_BUILDROOT_CXX=y
BR2_INIT_NONE=y
BR2_ROOTFS_DEVICE_CREATION_DYNAMIC_EUDEV=y
BR2_PACKAGE_MESA3D=y
BR2_PACKAGE_MESA3D_GALLIUM_DRIVER_NOUVEAU=y
BR2_PACKAGE_MESA3D_GALLIUM_DRIVER_R600=y
BR2_PACKAGE_MESA3D_GALLIUM_DRIVER_SVGA=y
BR2_PACKAGE_MESA3D_GALLIUM_DRIVER_SWRAST=y
BR2_PACKAGE_MESA3D_DRI_DRIVER_SWRAST=y
BR2_PACKAGE_MESA3D_DRI_DRIVER_I915=y
BR2_PACKAGE_MESA3D_DRI_DRIVER_I965=y
BR2_PACKAGE_MESA3D_DRI_DRIVER_RADEON=y
BR2_PACKAGE_MESA3D_OPENGL_EGL=y
BR2_PACKAGE_MESA3D_OPENGL_ES=y
BR2_PACKAGE_XORG7=y
BR2_PACKAGE_XSERVER_XORG_SERVER=y
BR2_PACKAGE_XSERVER_XORG_SERVER_MODULAR=y
BR2_PACKAGE_XDRIVER_XF86_VIDEO_INTEL=y

RRProviderPtr is defined in dri3/dri3.h, so make sure glamor is enabled only
if dri3 is enabled, too.

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Acked-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>