qnetworkreply automated test fails to link for QNX

qtbase/tests/auto/network/access/qnetworkreply/test fails to link for QNX because the application isn't being linked to the QNX socket library.  It appears to be a result of https://codereview.qt-project.org/c/qt/qtbase/+/248686.  I dug into the problem enough to find out that it's occurring because this change causes qmake to discard PRL files instead of accepting them.  With debug level 2, qmake reports the following when it finishes processing the Qt5Network PRL file:

DEBUG 2: Mismatched meta file /Users/jmcdonnell/qnx/qtbase-build/tmp-bad/qnx/700/x86_64/release/result/lib/libQt5Network.prl (want libQt5Network.so, got libQt5Network.so.5.12.3)

qmake discards the PRL file when this happens.