make vp9 postproc a config option

Vp9 postproc is disabled for now as its not been shown to help and
may be merged with vp8.

Change-Id: I25620d6cd34c6e10331b18c7b5ef7482e39c6057
diff --git a/configure b/configure
index a252081..e7f9f4f 100755
--- a/configure
+++ b/configure
@@ -38,6 +38,7 @@
   ${toggle_internal_stats}        output of encoder internal stats for debug, if supported (encoders)
   ${toggle_mem_tracker}           track memory usage
   ${toggle_postproc}              postprocessing
+  ${toggle_vp9_postproc}          vp9 specific postprocessing
   ${toggle_multithread}           multithreaded encoding and decoding
   ${toggle_spatial_resampling}    spatial sampling (scaling) support
   ${toggle_realtime_only}         enable this option while building for real-time encoding
@@ -279,6 +280,7 @@
     dc_recon
     runtime_cpu_detect
     postproc
+    vp9_postproc
     multithread
     internal_stats
     ${CODECS}
@@ -333,6 +335,7 @@
     dequant_tokens
     dc_recon
     postproc
+    vp9_postproc
     multithread
     internal_stats
     ${CODECS}
@@ -438,7 +441,7 @@
     done
     enabled debug_libs && DIST_DIR="${DIST_DIR}-debug"
     enabled codec_srcs && DIST_DIR="${DIST_DIR}-src"
-    ! enabled postproc && DIST_DIR="${DIST_DIR}-nopost"
+    ! enabled postproc && ! enabled vp9_postproc && DIST_DIR="${DIST_DIR}-nopost"
     ! enabled multithread && DIST_DIR="${DIST_DIR}-nomt"
     ! enabled install_docs && DIST_DIR="${DIST_DIR}-nodocs"
     DIST_DIR="${DIST_DIR}-${tgt_isa}-${tgt_os}"