Hi reviewers, this is a split version of the CL - https://reviews.llvm.org/D68062 which seems too big to review and submit in one shot.
What does this CL include:
- added Propeller config class PropellerConfig.h
- added interface to lld driver in LinkerPropeller.c/cpp.
- propeller flags handling
This CL is self-contained, buildable and non-functional. all real work is done in the origin https://reviews.llvm.org/D68062