wined3d: Test if result.clip[] works correctly.

The Mac Nvidia driver doesn't implement the result.clip part of
GL_NV_vertex_program2_option correctly. It complains about a syntax
error if "result.clip[0]" is used. "result.clip" compiles correctly, but
supports only one clipplane, and running the shader results in severe
rendering bugs.
diff --git a/dlls/wined3d/wined3d_private.h b/dlls/wined3d/wined3d_private.h
index 24066c9..b431a1b 100644
--- a/dlls/wined3d/wined3d_private.h
+++ b/dlls/wined3d/wined3d_private.h
@@ -48,6 +48,7 @@
 #define WINED3D_QUIRK_SET_TEXCOORD_W            0x00000002
 #define WINED3D_QUIRK_GLSL_CLIP_VARYING         0x00000004
 #define WINED3D_QUIRK_ALLOWS_SPECULAR_ALPHA     0x00000008
+#define WINED3D_QUIRK_NV_CLIP_BROKEN            0x00000010
 
 /* Texture format fixups */