RCC: Use macros not defined in qglobal.h

This prevents conflicts in case of link time optimizations or
precompiled headers are used since we don't include qglobal.h
in the generated code.

Change-Id: I4266c8ae38e6eafefd28b3bde5cb725a24d67ea0
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>