qxt does not build when Qt has been configured with -qtlibinfix

We use a Qt build that has been configured with -qtlibinfix XYZ in order to prevent clashes with oth)er Qt installations.

Building Qxt with such a Qt leads to the following situation: Qxt builds lib/libQxtCore.so but wants to link against a libQxtCoreXYZ which it cannot find of course.

(I wanted to give Qxt a try. Primarily because I need something like QxtGlobalShortcut.