Why are built in dlls preferred over native

[Vincent Povirk (they/them)]

In the case of gdiplus, the native dll has a critical bug that is not
present in builtin (crashing when encountering certain fonts). I also
remember there were regressions reported when we switched to
preferring builtin. The default did matter for people who didn't
intentionally install the native dll.

For d3d8, if anything installs native in a system location, that can't
work and we have to prefer builtin. (I can't verify right now, but I'd
guess that directx installers, which are run often especially on
steam, do that.)

In general, builtin is the better tested (with the rest of wine) and
more easily debugged path.

That said, we do prefer native for many libraries, particularly when
adding a new stub dll.