xlib does not support en_HK despite defined in shared data

[Michael Tsang]

when LC_ALL is en_HK.UTF-8, Xlib cannot use locale. This make me not able to use locale-aware applications such as input methods at that locale. There are no problems with other en locales such as en_GB.UTF-8

[michael@kubuntu ~]$ LC_ALL=en_HK.UTF-8 xeyes
Warning: locale not supported by Xlib, locale set to C
^C
[michael@kubuntu ~]$ LC_ALL=en_GB.UTF-8 xeyes
^C

ProblemType: Bug
DistroRelease: Ubuntu 15.04
Package: libx11-6 2:1.6.2-2ubuntu2
ProcVersionSignature: Ubuntu 3.19.0-25.26-generic 3.19.8-ckt2
Uname: Linux 3.19.0-25-generic x86_64
ApportVersion: 2.17.2-0ubuntu1.1
Architecture: amd64
CurrentDesktop: KDE
Date: Tue Aug 4 18:02:06 2015
InstallationDate: Installed on 2015-08-03 (1 days ago)
InstallationMedia: Kubuntu 15.04 "Vivid Vervet" - Release amd64 (20150422)
SourcePackage: libx11
UpgradeStatus: No upgrade log present (probably fresh install)