Spurious duplicate output from cmake-based configure

Found when building Qt from CI-approved commit 43291fd110 in the dev branch of qt5.git.

"configure -opensource" prints two consecutive copies of the following message immediately after the end of the long yes/no list of features.

 Note: No wayland-egl support detected. Cross-toolkit compatibility disabled.

In addition to the unnecessary duplication, it seems strange that this isn't just another entry in the yes/no list like everything else.