Fork channel

Create a new channel as a copy of main.

Rename channel

Rename main to:

Delete channel

Delete main? This cannot be undone.

debug-prefix-map.S
// RUN: %clang -### -g -fintegrated-as -fdebug-prefix-map=old=new %s 2>&1 | FileCheck %s
// RUN: %clang -### -g -fintegrated-as -ffile-prefix-map=old=new %s 2>&1 | FileCheck %s

// CHECK: cc1as
// CHECK-SAME: -fdebug-prefix-map=old=new

// More tests for this flag in debug-prefix-map.c.