make ifdef use a feature macro: VC_HAVE_ATTRIBUTE_WARNING
make ifdef use a feature macro: VC_HAVE_ATTRIBUTE_WARNING

chr-engwer/Vc,VcDevel/Vc,VcDevel/Vc,VcDevel/Vc,VcDevel/Vc,chr-engwer/Vc,chr-engwer/Vc