Linking error if XORG_PREFIX is custom

g++ -Wl,--no-undefined -Wl,-rpath,/opt/qt5/lib -shared -Wl,-Bsymbolic-functions -Wl,--dynamic-list,/usr/src/packages/qt-everywhere-opensource-src-5.1.0-beta1/qtbase/src/widgets/QtWidgets.dynlist -Wl,-soname,libQt5Widgets.so.5 -o libQt5Widgets.so.5.1.0 .obj/debug-shared/qaction.o .obj/debug-shared/qactiongroup.o .obj/debug-shared/qapplication.o .obj/debug-shared/qwidgetbackingstore.o .obj/debug-shared/qboxlayout.o .obj/debug-shared/qformlayout.o .obj/debug-shared/qgridlayout.o .obj/debug-shared/qlayout.o .obj/debug-shared/qlayoutengine.o .obj/debug-shared/qlayoutitem.o .obj/debug-shared/qshortcut.o .obj/debug-shared/qstackedlayout.o .obj/debug-shared/qtooltip.o .obj/debug-shared/qwhatsthis.o .obj/debug-shared/qwidget.o .obj/debug-shared/qwidgetaction.o .obj/debug-shared/qgesture.o .obj/debug-shared/qstandardgestures.o .obj/debug-shared/qgesturerecognizer.o .obj/debug-shared/qgesturemanager.o .obj/debug-shared/qdesktopwidget.o .obj/debug-shared/qwidgetsvariant.o .obj/debug-shared/qapplication_qpa.o .obj/debug-shared/qdesktopwidget_qpa.o .obj/debug-shared/qwidget_qpa.o .obj/debug-shared/qwidgetwindow.o .obj/debug-shared/qwindowcontainer.o .obj/debug-shared/qdrawutil.o .obj/debug-shared/qstyle.o .obj/debug-shared/qstyleanimation.o .obj/debug-shared/qstylefactory.o .obj/debug-shared/qstyleoption.o .obj/debug-shared/qstyleplugin.o .obj/debug-shared/qstylehelper.o .obj/debug-shared/qcommonstyle.o .obj/debug-shared/qproxystyle.o .obj/debug-shared/qstylepainter.o .obj/debug-shared/qstylesheetstyle.o .obj/debug-shared/qstylesheetstyle_default.o .obj/debug-shared/qwindowsstyle.o .obj/debug-shared/qgtkstyle.o .obj/debug-shared/qgtkpainter.o .obj/debug-shared/qgtk2painter.o .obj/debug-shared/qgtkstyle_p.o .obj/debug-shared/qfusionstyle.o .obj/debug-shared/qabstractbutton.o .obj/debug-shared/qabstractslider.o .obj/debug-shared/qabstractspinbox.o .obj/debug-shared/qcalendarwidget.o .obj/debug-shared/qcheckbox.o .obj/debug-shared/qcombobox.o .obj/debug-shared/qcommandlinkbutton.o .obj/debug-shared/qdatetimeedit.o .obj/debug-shared/qdial.o .obj/debug-shared/qdialogbuttonbox.o .obj/debug-shared/qdockwidget.o .obj/debug-shared/qdockarealayout.o .obj/debug-shared/qeffects.o .obj/debug-shared/qfontcombobox.o .obj/debug-shared/qframe.o .obj/debug-shared/qgroupbox.o .obj/debug-shared/qlabel.o .obj/debug-shared/qlcdnumber.o .obj/debug-shared/qlineedit_p.o .obj/debug-shared/qlineedit.o .obj/debug-shared/qmainwindow.o .obj/debug-shared/qmainwindowlayout.o .obj/debug-shared/qmdiarea.o .obj/debug-shared/qmdisubwindow.o .obj/debug-shared/qmenu.o .obj/debug-shared/qmenubar.o .obj/debug-shared/qprogressbar.o .obj/debug-shared/qpushbutton.o .obj/debug-shared/qradiobutton.o .obj/debug-shared/qrubberband.o .obj/debug-shared/qscrollbar.o .obj/debug-shared/qsizegrip.o .obj/debug-shared/qslider.o .obj/debug-shared/qspinbox.o .obj/debug-shared/qsplashscreen.o .obj/debug-shared/qsplitter.o .obj/debug-shared/qstackedwidget.o .obj/debug-shared/qstatusbar.o .obj/debug-shared/qtabbar.o .obj/debug-shared/qtabwidget.o .obj/debug-shared/qtextedit.o .obj/debug-shared/qtextbrowser.o .obj/debug-shared/qtoolbar.o .obj/debug-shared/qtoolbarlayout.o .obj/debug-shared/qtoolbarextension.o .obj/debug-shared/qtoolbarseparator.o .obj/debug-shared/qtoolbox.o .obj/debug-shared/qtoolbutton.o .obj/debug-shared/qabstractscrollarea.o .obj/debug-shared/qwidgetresizehandler.o .obj/debug-shared/qfocusframe.o .obj/debug-shared/qscrollarea.o .obj/debug-shared/qwidgetanimator.o .obj/debug-shared/qwidgettextcontrol.o .obj/debug-shared/qwidgetlinecontrol.o .obj/debug-shared/qtoolbararealayout.o .obj/debug-shared/qplaintextedit.o .obj/debug-shared/qcolordialog.o .obj/debug-shared/qdialog.o .obj/debug-shared/qerrormessage.o .obj/debug-shared/qfiledialog.o .obj/debug-shared/qfontdialog.o .obj/debug-shared/qinputdialog.o .obj/debug-shared/qmessagebox.o .obj/debug-shared/qprogressdialog.o .obj/debug-shared/qsidebar.o .obj/debug-shared/qfilesystemmodel.o .obj/debug-shared/qfileinfogatherer.o .obj/debug-shared/qwizard.o .obj/debug-shared/qaccessiblewidget.o .obj/debug-shared/qabstractitemview.o .obj/debug-shared/qheaderview.o .obj/debug-shared/qlistview.o .obj/debug-shared/qbsptree.o .obj/debug-shared/qtableview.o .obj/debug-shared/qtreeview.o .obj/debug-shared/qabstractitemdelegate.o .obj/debug-shared/qitemdelegate.o .obj/debug-shared/qdirmodel.o .obj/debug-shared/qlistwidget.o .obj/debug-shared/qtablewidget.o .obj/debug-shared/qtreewidget.o .obj/debug-shared/qitemeditorfactory.o .obj/debug-shared/qtreewidgetitemiterator.o .obj/debug-shared/qdatawidgetmapper.o .obj/debug-shared/qfileiconprovider.o .obj/debug-shared/qcolumnview.o .obj/debug-shared/qcolumnviewgrip.o .obj/debug-shared/qstyleditemdelegate.o .obj/debug-shared/qgraphicsgridlayout.o .obj/debug-shared/qgraphicsitem.o .obj/debug-shared/qgraphicsitemanimation.o .obj/debug-shared/qgraphicslayout.o .obj/debug-shared/qgraphicslayout_p.o .obj/debug-shared/qgraphicslayoutitem.o .obj/debug-shared/qgraphicslinearlayout.o .obj/debug-shared/qgraphicsproxywidget.o .obj/debug-shared/qgraphicsscene.o .obj/debug-shared/qgraphicsscene_bsp.o .obj/debug-shared/qgraphicsscenebsptreeindex.o .obj/debug-shared/qgraphicssceneevent.o .obj/debug-shared/qgraphicssceneindex.o .obj/debug-shared/qgraphicsscenelinearindex.o .obj/debug-shared/qgraphicstransform.o .obj/debug-shared/qgraphicsview.o .obj/debug-shared/qgraphicswidget.o .obj/debug-shared/qgraphicswidget_p.o .obj/debug-shared/qgridlayoutengine.o .obj/debug-shared/qsimplex_p.o .obj/debug-shared/qgraphicsanchorlayout_p.o .obj/debug-shared/qgraphicsanchorlayout.o .obj/debug-shared/qsystemtrayicon.o .obj/debug-shared/qcolormap.o .obj/debug-shared/qcompleter.o .obj/debug-shared/qscroller.o .obj/debug-shared/qscrollerproperties.o .obj/debug-shared/qflickgesture.o .obj/debug-shared/qundogroup.o .obj/debug-shared/qundostack.o .obj/debug-shared/qundoview.o .obj/debug-shared/qsystemtrayicon_x11.o .obj/debug-shared/qguistatemachine.o .obj/debug-shared/qkeyeventtransition.o .obj/debug-shared/qmouseeventtransition.o .obj/debug-shared/qbasickeyeventtransition.o .obj/debug-shared/qbasicmouseeventtransition.o .obj/debug-shared/qgraphicseffect.o .obj/debug-shared/qpixmapfilter.o .obj/debug-shared/qrc_qstyle.o .obj/debug-shared/qrc_qmessagebox.o .obj/debug-shared/moc_qboxlayout.o .obj/debug-shared/moc_qdesktopwidget.o .obj/debug-shared/moc_qformlayout.o .obj/debug-shared/moc_qgridlayout.o .obj/debug-shared/moc_qlayout.o .obj/debug-shared/moc_qshortcut.o .obj/debug-shared/moc_qsizepolicy.o .obj/debug-shared/moc_qstackedlayout.o .obj/debug-shared/moc_qdesktopwidget_qpa_p.o .obj/debug-shared/moc_qwidgetwindow_qpa_p.o .obj/debug-shared/moc_qwindowcontainer_p.o .obj/debug-shared/moc_qstyle.o .obj/debug-shared/moc_qstyleanimation_p.o .obj/debug-shared/moc_qstyleplugin.o .obj/debug-shared/moc_qproxystyle.o .obj/debug-shared/moc_qwindowsstyle_p.o .obj/debug-shared/moc_qgtkstyle_p.o .obj/debug-shared/moc_qgtkstyle_p_p.o .obj/debug-shared/moc_qfusionstyle_p.o .obj/debug-shared/moc_qbuttongroup.o .obj/debug-shared/moc_qabstractbutton.o .obj/debug-shared/moc_qabstractslider.o .obj/debug-shared/moc_qcalendartextnavigator_p.o .obj/debug-shared/moc_qcheckbox.o .obj/debug-shared/moc_qcombobox_p.o .obj/debug-shared/moc_qcommandlinkbutton.o .obj/debug-shared/moc_qdatetimeedit_p.o .obj/debug-shared/moc_qdial.o .obj/debug-shared/moc_qdockwidget_p.o .obj/debug-shared/moc_qframe.o .obj/debug-shared/moc_qlcdnumber.o .obj/debug-shared/moc_qmainwindow.o .obj/debug-shared/moc_qmainwindowlayout_p.o .obj/debug-shared/moc_qprogressbar.o .obj/debug-shared/moc_qradiobutton.o .obj/debug-shared/moc_qrubberband.o .obj/debug-shared/moc_qscrollbar.o .obj/debug-shared/moc_qslider.o .obj/debug-shared/moc_qspinbox.o .obj/debug-shared/moc_qsplashscreen.o .obj/debug-shared/moc_qsplitter.o .obj/debug-shared/moc_qstackedwidget.o .obj/debug-shared/moc_qstatusbar.o .obj/debug-shared/moc_qtabbar_p.o .obj/debug-shared/moc_qtoolbarlayout_p.o .obj/debug-shared/moc_qtoolbarextension_p.o .obj/debug-shared/moc_qtoolbarseparator_p.o .obj/debug-shared/moc_qwidgetresizehandler_p.o .obj/debug-shared/moc_qfocusframe.o .obj/debug-shared/moc_qscrollarea.o .obj/debug-shared/moc_qwidgetanimator_p.o .obj/debug-shared/moc_qwidgetlinecontrol_p.o .obj/debug-shared/moc_qerrormessage.o .obj/debug-shared/moc_qsidebar_p.o .obj/debug-shared/moc_qfileinfogatherer_p.o .obj/debug-shared/moc_qlistview.o .obj/debug-shared/moc_qabstractitemdelegate.o .obj/debug-shared/moc_qlistwidget_p.o .obj/debug-shared/moc_qtablewidget_p.o .obj/debug-shared/moc_qtreewidget_p.o .obj/debug-shared/moc_qitemeditorfactory_p.o .obj/debug-shared/moc_qcolumnviewgrip_p.o .obj/debug-shared/moc_qgraphicsitemanimation.o .obj/debug-shared/moc_qgraphicsscenelinearindex_p.o .obj/debug-shared/moc_qgraphicswidget.o .obj/debug-shared/moc_qgraphicsanchorlayout.o .obj/debug-shared/moc_qcompleter_p.o .obj/debug-shared/moc_qsystemtrayicon_p.o .obj/debug-shared/moc_qscroller.o .obj/debug-shared/moc_qscroller_p.o .obj/debug-shared/moc_qflickgesture_p.o .obj/debug-shared/moc_qundogroup.o .obj/debug-shared/moc_qundostack.o .obj/debug-shared/moc_qundostack_p.o .obj/debug-shared/moc_qundoview.o .obj/debug-shared/moc_qkeyeventtransition.o .obj/debug-shared/moc_qmouseeventtransition.o .obj/debug-shared/moc_qbasickeyeventtransition_p.o .obj/debug-shared/moc_qbasicmouseeventtransition_p.o .obj/debug-shared/moc_qgraphicseffect.o .obj/debug-shared/moc_qgraphicseffect_p.o .obj/debug-shared/moc_qpixmapfilter_p.o  -L/usr/src/packages/qt-everywhere-opensource-src-5.1.0-beta1/qtbase/lib -lQt5Gui -lQt5Core -lpthread -lgobject-2.0 -lglib-2.0 -lXext -lX11 -lm 
/usr/bin/ld: cannot find -lXext