Revert "Remove the LIBS from platformsupport"

This reverts commit cd6e90c70a.

Prevent symbol lookup error when requesting alpha visuals with GLX in
the xcb plugin. This means other plugins will also link against
-lXrender, but we need this workaround for now.

Change-Id: I2fd2c63bc577c2497060a555c91d72337723b931
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@nokia.com>
Reviewed-by: Jørgen Lind <jorgen.lind@nokia.com>

src/platformsupport/glxconvenience/glxconvenience.pri

@@ -1,5 +1,6 @@
 contains(QT_CONFIG,xlib):contains(QT_CONFIG,xrender) {
     contains(QT_CONFIG,opengl):!contains(QT_CONFIG,opengles2) {
+        LIBS += $$QMAKE_LIBS_X11 -lXrender
         HEADERS += $$PWD/qglxconvenience_p.h
         SOURCES += $$PWD/qglxconvenience.cpp
     }

src/platformsupport/udev/udev.pri

@@ -3,4 +3,5 @@ contains(QT_CONFIG, libudev) {
     SOURCES += $$PWD/qudevicehelper.cpp
 
     INCLUDEPATH += $$QMAKE_INCDIR_LIBUDEV
+    LIBS += -ludev
 }