Sorry didn't get these done sooner, hope I didn't hold up your work.
Found some info on the issue I was seeing with QtPrintSupport missing, so added a second qt version check in qcustomplot.h - appears to be a bug in the toolchain.
Code:#if QT_VERSION < QT_VERSION_CHECK(5, 0, 0) || QT_VERSION > QT_VERSION_CHECK(5, 7, 0)
# include <qnumeric.h> // workaround for bug in qt 5.8 and newer
# include <QPrinter> // https://bugreports.qt.io/browse/QTBUG-56321