depends: qt: Explicitly stop using Xlib/libX11
depends: qt: Explicitly stop using Xlib/libX11

Previously, in 683b7d7a3fc1b9240333faf3d04497aa61583016 and
0e752637a26cf75187864a466db9a92540a2d3c8, we accidentally broke QT's
ability to pick up Xlib thru the config.gui.tests.xlib configuration
test, which also means that config.gui.libraries.xcb_xlib wasn't run.

This resulted in a QT build that was implicitly -no-xcb-lib and
-no-feature-xlib.

This is actually a desired behaviour, as it means less required shared
objects for our final bitcoin-qt binary. Specifically, it eliminated the
libX11-xcb.so.1 and libX11.so.6 requirements.

In this commit, we explicitly build without Xlib. We should continue to
track upstream ticket https://bugreports.qt.io/browse/QTBUG-61452 which
talks about adding a -no-xlib (non-hidden) flag instead of the
-no-feature-xlib (hidden) flag.


Former-commit-id: acc051e70820994d1ec05aecd0eecac986aa8015
syscoin/syscoin2,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin2,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin2,syscoin/syscoin2,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin2,syscoin/syscoin2