Request: Improvements for xevc

[LigH-de]

Binaries get installed in local##/bin-video so that xeve_app.exe / xevd_app.exe and libxeve.dll / libxevd.dll both end up there, although the DLLs are not required by the EXEs.

Furthermore, in local##/lib two empty directories xeve and xevd exist (probably superfluous), and both libxeve.a / libxevd.a and libxeve.dll.a.dyn / libxevd.dll.a.dyn; I guess the latter are not so important when the suite builds for a static ffmpeg target.

And I believe you wanted to make them a selectable choice in the batch as well.

[L4cache]

The dynamic libraries will always be built, no simple way to turn off, I thought.
Subdirectories were created by them during installation and are where the libraries (.a and .dll.a) went, but usually that makes them hard to be found by ffmpeg so I moved them out, and didn't delete the subdirectories...

[LigH-de]

I don't mind if some of this issue "won't fix", nothing important.