Fix build for orc 0.4.30 and later
Taken from https://anonhg.netbsd.org/pkgsrc/rev/b7ba46cae228

--- ext/libpostproc/gstpostproc.c.orig	2011-07-12 23:35:27.000000000 +0900
+++ ext/libpostproc/gstpostproc.c	2019-10-14 22:25:15.311639480 +0900
@@ -299,7 +299,7 @@ change_context (GstPostProc * postproc, 
     ppflags = (mmx_flags & ORC_TARGET_MMX_MMX ? PP_CPU_CAPS_MMX : 0)
         | (mmx_flags & ORC_TARGET_MMX_MMXEXT ? PP_CPU_CAPS_MMX2 : 0)
         | (mmx_flags & ORC_TARGET_MMX_3DNOW ? PP_CPU_CAPS_3DNOW : 0)
-        | (altivec_flags & ORC_TARGET_ALTIVEC_ALTIVEC ? PP_CPU_CAPS_ALTIVEC :
+        | (altivec_flags & ORC_TARGET_POWERPC_ALTIVEC ? PP_CPU_CAPS_ALTIVEC :
         0);
 #else
     mmx_flags = 0;
--- ext/libswscale/gstffmpegscale.c.orig	2011-11-02 22:04:05.000000000 +0900
+++ ext/libswscale/gstffmpegscale.c	2019-10-14 22:19:36.351245163 +0900
@@ -638,7 +638,7 @@ gst_ffmpegscale_set_caps (GstBaseTransfo
   swsflags = (mmx_flags & ORC_TARGET_MMX_MMX ? SWS_CPU_CAPS_MMX : 0)
       | (mmx_flags & ORC_TARGET_MMX_MMXEXT ? SWS_CPU_CAPS_MMX2 : 0)
       | (mmx_flags & ORC_TARGET_MMX_3DNOW ? SWS_CPU_CAPS_3DNOW : 0)
-      | (altivec_flags & ORC_TARGET_ALTIVEC_ALTIVEC ? SWS_CPU_CAPS_ALTIVEC : 0);
+      | (altivec_flags & ORC_TARGET_POWERPC_ALTIVEC ? SWS_CPU_CAPS_ALTIVEC : 0);
 #else
   mmx_flags = 0;
   altivec_flags = 0;