configure: opengl doesn't depend on x11

So remove x11 from pkg-config check and don't
add x11 cflags/libs to opengl cflags/libs.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Message-id: 20180301100547.18962-10-kraxel@redhat.com

configure

@@ -3779,9 +3779,9 @@ libs_softmmu="$libs_softmmu $fdt_libs"
 
 if test "$opengl" != "no" ; then
   opengl_pkgs="epoxy libdrm gbm"
-  if $pkg_config $opengl_pkgs x11; then
-    opengl_cflags="$($pkg_config --cflags $opengl_pkgs) $x11_cflags"
-    opengl_libs="$($pkg_config --libs $opengl_pkgs) $x11_libs"
+  if $pkg_config $opengl_pkgs; then
+    opengl_cflags="$($pkg_config --cflags $opengl_pkgs)"
+    opengl_libs="$($pkg_config --libs $opengl_pkgs)"
     opengl=yes
     if test "$gtk" = "yes" && $pkg_config --exists "$gtkpackage >= 3.16"; then
         gtk_gl="yes"