https://bugs.winehq.org/show_bug.cgi?id=57308
--- Comment #1 from Rafał Mużyło galtgendo@o2.pl --- ...yeah, about that: on Linux that usually works though an ELF tag; libs under x86_64-windows are cross-compiled Windows DLLs - those use different mechanism and I wouldn't be surprised if - if anything like that is even possible (it might be) - the files with symbols needed to be in the same path as their libs, perhaps even mandatorily in pdb format.
:shrug: Gentoo skips stripping dlls, only doing it with ELF libraries.