I'm trying to build the 3.5.13 packages from the tarballs. I keep seeing the following error: checking for Qt... checking for pkg-config... /usr/bin/pkg-config configure: error: Qt (>= Qt 4.3 and < 5.0) (library QtCore -lQtGui -lQtNetwork -ltqt-mt) not found. Please check your installation! I looked at the logs, configure, etc., but I don't see anything obvious. What is the magic trick? Darrell