--- qt5-build.eclass.orig	2018-02-18 13:54:12.549290277 +0100
+++ qt5-build.eclass.orig	2018-02-18 13:54:48.292622028 +0100
@@ -686,6 +686,9 @@ qt5_base_configure() {
 		# enable in respective modules to avoid poisoning QT.global_private.enabled_features
 		$([[ ${QT5_MINOR_VERSION} -ge 9 ]] && echo -no-gui -no-widgets)
 
+		# Add custom configuration flags
+		"${EXTRA_ECONF}"
+
 		# module-specific options
 		"${myconf[@]}"
 	)