Passing -developer-build to configure ends up passing -DINPUT_developer_build=ON to cmake. The translation from INPUT_developer_build to FEATURE_developer_build happens later than computation of the prefix location.

This causes cmake to create a prefix build, rather than a non-prefix build.

Automatic translation happens somewhere at corelib's qt_feature_module_end() time
whereas prefix computation happens really early at QtSetup.cmake time.