support injecting link options

[bashbaug]

Observed Behavior

We can currently inject build options and compile options but not link options.

Desired Behavior

Support injecting link options also.

Note that this is a little trickier (or at least different) than injecting build and compile options because we don't have a program object yet when we need to check for link options to inject.

Steps to Reproduce

1. Run a program that compiles and links a program separately and provides link options.
2. Dump link options.
3. Copy the link options to the Inject folder and enable program injection.
4. No link options are injected.