#829 CMake: Qt5X11Extras not always necessary

[liangtai]

Hi,

On CMake build for Qt5-based codes, src/CMakeLists.txt requires Qt5X11Extras
library even if I set -DUSE_HOTKEY:BOOL=FALSE -DUSE_SKINNED:BOOL=FALSE, but
it seems other base components and plugins does not depend on the library.

find_package(Qt5X11Extras 5.4.0 REQUIRED)

[trialuser02]

Fixed in svn. Thank you!