[REG2.065a] Issue 11931 - Linkers "Symbol Undefined" again with dmd HEAD when -g specified 

https://d.puremagic.com/issues/show_bug.cgi?id=11931

I had misunderstood about the root cause of [regression 11863](https://d.puremagic.com/issues/show_bug.cgi?id=11931).