Bug 2955. Workaround for lack of atomic operations in GCCE standard libraries (fall back to default use of Mutex)

INCLUDEPATH += $$QMAKE_INCDIR_X11
QMAKE_CFLAGS += $$QMAKE_CFLAGS_X11
QMAKE_CXXFLAGS += $$QMAKE_CFLAGS_X11