libandroid-posix-semaphore support for qt5 And PyQt5

[ar664]

I suggest building with semaphore support now that we have libandroid-posix-semaphore.
https://github.com/termux/x11-packages/blob/ae193d67e3f0bda6a591e94c2410ab27badd7c8c/packages/qt5-qtbase/termux-build-qmake.sh#L79

Because when I try to do pip install PyQt5 this is the current error I get.

[ar664]

Update to PyQt5 build errors after pr termux/x11-packages#632 .

I assume the Qt5Core could be built with -system-proxies instead of -no-system-proxies

[xtkoba]

IPC support for Qt5 has already been added. As for PyQt5, please migrate to #10165. Thanks.