0028838: Configuration - undefine macros coming from X11 headers in place of collision

0028838: Configuration - undefine macros coming from X11 headers in place of collision

The macros Status, Convex, Opposite, FillSolid (coming from X11 headers)
are now undefined in place of definition of methods with same name in OCCT headers.
The usage of variables with name Status is now avoided.

GL_GLEXT_LEGACY is now defined only if not already defined.

The macros AddPrinter (coming from WinAPI headers) is now undefined
within Message_Messenger class definition having method with the same name.
CurrentDirectory macro is now undefined in OSD_Process.hxx.