Fork channel

Create a new channel as a copy of main.

Rename channel

Rename main to:

Delete channel

Delete main? This cannot be undone.

undef-error.c
// RUN: %clang_cc1 %s -pedantic-errors -Wno-empty-translation-unit -verify 
// PR2045

#define b
/* expected-error {{extra tokens at end of #undef directive}} */ #undef a b