Don't set "-g" for the entire compilation, and deny any user-requested g-group
arguments. When operating as "-cc1", set the CompilerInvocation to generate
full debug info. This prevents the Driver from running dsymutil, which would
complain if the intermediate object created by seec-ld did not exist. Using
traditional debugging on an instrumented executable would be confusing due to
the additional code added by SeeC, so there is no need to support the user
requesting debugging information.