gst-plugins-bad: add libvpx-1.4.0 patch from Arch.

srcpkgs/gst-plugins-bad/patches/drop-vpx-compat-defs.patch

@@ -0,0 +1,26 @@
+--- ext/vp8/gstvp8utils.h	2015-04-21 03:31:33.134952881 +0300
++++ ext/vp8/gstvp8utils.h	2015-04-21 03:32:45.553520671 +0300
+@@ -25,23 +25,6 @@
+ 
+ G_BEGIN_DECLS
+ 
+-/* Some compatibility defines for older libvpx versions */
+-#ifndef VPX_IMG_FMT_I420
+-#define VPX_IMG_FMT_I420 IMG_FMT_I420
+-#endif
+-
+-#ifndef VPX_PLANE_Y
+-#define VPX_PLANE_Y PLANE_Y
+-#endif
+-
+-#ifndef VPX_PLANE_U
+-#define VPX_PLANE_U PLANE_U
+-#endif
+-
+-#ifndef VPX_PLANE_V
+-#define VPX_PLANE_V PLANE_V
+-#endif
+-
+ const char * gst_vpx_error_name (vpx_codec_err_t status);
+ 
+ G_END_DECLS