Add config flag for new_quant experiment

Change-Id: I3575f688ad473d9750a16c7dae74f5f97d026b26
diff --git a/configure b/configure
index 1fe9acd..123e9c4 100755
--- a/configure
+++ b/configure
@@ -281,6 +281,7 @@
     ext_interp
     ext_refs
     global_motion
+    new_quant
     supertx
     ans
     loop_restoration