Define return_trace()

Not functional change (expected!).
diff --git a/src/hb-open-file-private.hh b/src/hb-open-file-private.hh
index 178bc7c..152230a 100644
--- a/src/hb-open-file-private.hh
+++ b/src/hb-open-file-private.hh
@@ -56,7 +56,7 @@
   inline bool sanitize (hb_sanitize_context_t *c) const
   {
     TRACE_SANITIZE (this);
-    return TRACE_RETURN (c->check_struct (this));
+    return_trace (c->check_struct (this));
   }
 
   Tag		tag;		/* 4-byte identifier. */
@@ -106,7 +106,7 @@
   inline bool sanitize (hb_sanitize_context_t *c) const
   {
     TRACE_SANITIZE (this);
-    return TRACE_RETURN (c->check_struct (this) && c->check_array (tables, TableRecord::static_size, numTables));
+    return_trace (c->check_struct (this) && c->check_array (tables, TableRecord::static_size, numTables));
   }
 
   protected:
@@ -135,7 +135,7 @@
   inline bool sanitize (hb_sanitize_context_t *c) const
   {
     TRACE_SANITIZE (this);
-    return TRACE_RETURN (table.sanitize (c, this));
+    return_trace (table.sanitize (c, this));
   }
 
   protected:
@@ -175,11 +175,11 @@
   inline bool sanitize (hb_sanitize_context_t *c) const
   {
     TRACE_SANITIZE (this);
-    if (unlikely (!u.header.version.sanitize (c))) return TRACE_RETURN (false);
+    if (unlikely (!u.header.version.sanitize (c))) return_trace (false);
     switch (u.header.version.major) {
     case 2: /* version 2 is compatible with version 1 */
-    case 1: return TRACE_RETURN (u.version1.sanitize (c));
-    default:return TRACE_RETURN (true);
+    case 1: return_trace (u.version1.sanitize (c));
+    default:return_trace (true);
     }
   }
 
@@ -240,14 +240,14 @@
   inline bool sanitize (hb_sanitize_context_t *c) const
   {
     TRACE_SANITIZE (this);
-    if (unlikely (!u.tag.sanitize (c))) return TRACE_RETURN (false);
+    if (unlikely (!u.tag.sanitize (c))) return_trace (false);
     switch (u.tag) {
     case CFFTag:	/* All the non-collection tags */
     case TrueTag:
     case Typ1Tag:
-    case TrueTypeTag:	return TRACE_RETURN (u.fontFace.sanitize (c));
-    case TTCTag:	return TRACE_RETURN (u.ttcHeader.sanitize (c));
-    default:		return TRACE_RETURN (true);
+    case TrueTypeTag:	return_trace (u.fontFace.sanitize (c));
+    case TTCTag:	return_trace (u.ttcHeader.sanitize (c));
+    default:		return_trace (true);
     }
   }