CMake: Map xkbcommon_support

Qt 5.12 comes with xkbcommon_support now. Map that accordingly.

Change-Id: Id10708349d377f6bdfed654428ebcef0b533bd69
Reviewed-by: Albert Astals Cid <albert.astals.cid@kdab.com>

util/cmake/helper.py

@@ -152,6 +152,7 @@ def map_qt_base_library(lib: str) -> str:
         'winextras': 'Qt::WinExtras',
         'x11extras': 'Qt::X11Extras',
         'xcb_qpa_lib': 'Qt::XcbQpa',
+        'xkbcommon_support': 'Qt::XkbCommonSupport',
         'xmlpatterns': 'Qt::XmlPatterns',
         'xml': 'Qt::Xml',
     }