Changes needed for coroutine support

[kennykb]

Donal,

These are changes that we will need in order to have quadcode generate calls to the LLVM coroutine intrinsics. I'll follow up with details on the mailing list.

Kevin

Change log:
Silence many warnings when building with gcc.

Add 'ParseCommandLineOptions' to allow for changing unexported options
such as '-debug-pass'

Add 'addCoroutinePassesToExtensionPoints' so that generated code can
use LLVM coroutines.

[kennykb]

D'oh! Need to advance the minor version to advertise the API change. Another commit made.

[dkfellows]

Looks good; there's a few places where I'd do things a bit differently myself, but I tend to think that's not a reason for pushing back.

[dkfellows]

The changes that I needed on the end were:

1. Added coroutines to the list of components. Some LLVM builds (those that use .a files) split themselves up into many libraries (“components”) and the coroutine support needed to be added for my system.
2. Made the command line argument parser not keel the Tcl process over if it detects an error. It's up to the calling Tcl code to make that sort of decision.

Alas, I only detected the first issue after the merge (the second wasn't a build breaker).