fcitx-qt5: kde5PackagesFun -> qt5LibsFun

[ericsagnes]

Things done

• Tested using sandboxing
  (nix.useSandbox on NixOS,
  or option build-use-sandbox in nix.conf
  on non-NixOS)
• Built on platform(s)
  • NixOS
  • OS X
  • Linux
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Fits CONTRIBUTING.md.

---

This PR goal is to remove extra-cmake-modules dependency from fcitx-qt5 so it can be moved from kde5PackagesFun to qt5LibsFun and be used with any versions of Qt5.

This address #15569 and should be tested and merged with #15498 fix.

fcitx-qt5 was only using a few extra-cmake-modules functions, so I chose the simple approach to patch the source to bring the needed modules.
Any improvement/feedback is welcomed.

I have tested this with in fcitx-wrapper:
- qt5.fcitx-qt5 -> kate (qt56) is working, qutebrowser (qt55) is not
- qt55.fcitx-qt5 -> kate (qt56) is not working, qutebrowser (qt55) is

Update (2016-05-21):

I changed the commit to use the modules from kde5.extra-cmake-modules directly by linking them in fcitx-qt5 source, that way can use the few required extra cmake modules without having fcitx-qt5 be part of kde5PackagesFun, and this make the patch much lighter.

By using qt55.fcitx-qt5 in fcitx-wrapper, fcitx is working fine in Qt 5.5 and Qt 5.6 applications (tested with kate and qutebrowser).

I don't know the reason, but suppose that this is due to the plugin ABI being compatible between these 2 versions.

So this PR will improve the situation as soon as it gets merged, and because it moves fcitx-qt5 to qt5LibsFun, should help fcitx-qt5 to be integrated in #15498 fix.

cc @ttuegel

[mention-bot]

By analyzing the blame information on this pull request, we identified @abbradar and @cdepillabout to be potential reviewers

[ericsagnes]

Updated the commit and the issue description.

[zimbatm]

thanks !

[ericsagnes]

Thanks for merging!