Implementation of --allow-multiple-definition flag
For tests I created 2 functions with the same name but different first instruction. Then checking that order of files in linker cmd line affects on which one is used.
Should anything else be checked ?
Usually when we concatenate strings, we use Twine. The new code uses String::operator+ instead, which is less preferred way to do the same thing. This would be better.
I also dropped "const" since it's obvious (and that use is more consistent with other code in LLD).