Add a CI job that uses LLVM linker (ld.lld) instead of GNU linker (ld)

[bratpiorka]

Add a CI job that uses LLVM linker (ld.lld) instead of GNU linker (ld).
It can be enabled with "-fuse-ld=lld" clang option.

related to #646

[pbalcer]

also make sure that it can detect issues with our map/def files.