- This allows 'swift <FOO>' to be used to invoke swift-<FOO>, so that we can
use 'swift' as a namespace for additional commands (like ones used for the
package manager.
- This patch just adds the basic subcommand functionality, but doesn't rework
either 'swift-autolink-extract' or 'swift -frontend' to follow this code path.
- <rdar://problem/22844530> Provide 'swift' support for subcommands
Swift SVN r32367