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-meta-data.test
# RUN: llvm-objdump --macho --objc-meta-data %p/Inputs/empty.macho-armv7 | FileCheck %s

# CHECK: empty.macho-armv7: