temporary fix because of alpha, has to be dropped as soon as gcc's bug is fixed.

--- a/src/opengl/opengl.pro
+++ b/src/opengl/opengl.pro
@@ -35,6 +35,7 @@ SOURCES	+= qgl.cpp \
            qglextensions.cpp \
            qglpaintdevice.cpp \
 
+QMAKE_CXXFLAGS_HIDESYMS -= -fvisibility-inlines-hidden
 
 !contains(QT_CONFIG, opengles2) {
     HEADERS += qpaintengine_opengl_p.h