Issue #2335: Backport set literals syntax from Python 3.x.
diff --git a/Python/compile.c b/Python/compile.c
index 03875a5..c8cab1c 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -808,6 +808,7 @@
 			return 1;
 		case BUILD_TUPLE:
 		case BUILD_LIST:
+		case BUILD_SET:
 			return 1-oparg;
 		case BUILD_MAP:
 			return 1;
@@ -2894,6 +2895,11 @@
 			ADDOP(c, STORE_MAP);
 		}
 		break;
+	case Set_kind:
+		n = asdl_seq_LEN(e->v.Set.elts);
+		VISIT_SEQ(c, expr, e->v.Set.elts);
+		ADDOP_I(c, BUILD_SET, n);
+		break;
 	case ListComp_kind:
 		return compiler_listcomp(c, e);
 	case GeneratorExp_kind: