[llvm] r254435 - Use a forwarding constructor instead of an init method.

[Rafael Espíndola via llvm-commits]

>> -Linker::Linker(Module *M, DiagnosticHandlerFunction DiagnosticHandler) {
>> -  init(M, DiagnosticHandler);
>> -}
>> -
>> -Linker::Linker(Module *M) {
>> -  init(M, [this](const DiagnosticInfo &DI) {
>> -    Composite->getContext().diagnose(DI);
>> -  });
>> -}
>> +Linker::Linker(Module *M)
>> +    : Linker(M,
>
> We can use these now?!  I missed that memo.
>

It is not in the coding standard, but I have seem them being used
before. Not sure when did we start. Unfortunately they are fairly hard
to grep for.

Cheers,
Rafael