CMake: Use a Find module for Zydis/Zycore

[crueter]

Much like the prior xxhash PR. This one also has the advantage of making
it completely trivial to handle distros that also install zy{dis,core}-config.cmake
alongside the PkgConfig files (Gentoo being one of them, tested it
here).

Signed-off-by: crueter [email protected]

[pmatos]

This was what I originally implemented but according to @neobrain this is not a good idea as some distros don't ship cmake files.

[crueter]

This was what I originally implemented but according to @neobrain this is not a good idea as some distros don't ship cmake files.

That's why I have the fallback:

find_package(Zycore QUIET CONFIG)

if (Zycore_CONSIDERED_CONFIGS)
    find_package_handle_standard_args(Zycore CONFIG_MODE)
else()

Basically if it finds a zycore-config.cmake, it will set Zycore_CONSIDERED_CONFIGS to ON and then find_package_handle_standard_args will pass that to the caller. If it doesn't find a zycore-config.cmake it sets Zycore_CONSIDERED_CONFIGS to OFF and goes through the standard pkgconfig procedure.

I tested on a distro without CMake files for zy* and it worked fine, though of course more tests on Fedora and the like would be nice.