Fork channel

Create a new channel as a copy of main.

Rename channel

Rename main to:

Delete channel

Delete main? This cannot be undone.

objc-pp.m
// RUN: %clang_cc1 %s -fsyntax-only -verify -pedantic -ffreestanding
// expected-no-diagnostics

#import <stdint.h>  // no warning on #import in objc mode.