[XeTeX] XeTeX/xdvipdfmx: PDF text copying with double encoded fonts

[Akira Kakuto]

Hi Jiang,

> Thank you for building this. I'm not familiar with w32tex, can users
> replace the same file from their TexLive 2017 installation?

Yes, I think that dvipdfmx.dll in the TeX Live 2017 can be replaced by
the new dvipdfmx.dll.

Best,
Akira