Fix build at top of trunk

Introduced in Change-Id: If9d98e49cee63f40085b179652bfacc31ff462ea

BUG=aomedia:527

Change-Id: Idfa609dc05a5981d83fa5d77c8c51b02bdf9abef

av1/common/reconinter.c

diff --git a/av1/common/reconinter.c b/av1/common/reconinter.c
index f0d5249..7ddda6f 100644
--- a/av1/common/reconinter.c
+++ b/av1/common/reconinter.c
@@ -915,6 +915,10 @@
   (void)cm;
 #endif
 
+#if CONFIG_MOTION_VAR && (CONFIG_CHROMA_SUB8X8 || !CONFIG_CB4X4)
+  const int build_for_obmc = !(mi_col_offset == 0 && mi_row_offset == 0);
+#endif  // CONFIG_MOTION_VAR && (CONFIG_CHROMA_SUB8X8 || !CONFIG_CB4X4)
+
 #if CONFIG_CHROMA_SUB8X8
   const BLOCK_SIZE bsize = mi->mbmi.sb_type;
   int sub8x8_inter = bsize < BLOCK_8X8 && plane > 0;
@@ -927,7 +931,6 @@
         sub8x8_inter = 0;
 
 #if CONFIG_MOTION_VAR
-  const int build_for_obmc = !(mi_col_offset == 0 && mi_row_offset == 0);
   if (!build_for_obmc && sub8x8_inter) {
 #else
   if (sub8x8_inter) {
@@ -1060,6 +1063,8 @@
     for (ref = 0; ref < 2; ++ref) pd->pre[ref] = orig_pred_buf[ref];
     return;
   }
+#else
+  (void)cm;
 #endif  // CONFIG_CHROMA_SUB8X8
 
   {