work around MSVC stupidity (part 2): it fails to understand this template specialization, so make it less strict...
work around MSVC stupidity (part 2): it fails to understand this template specialization, so make it less strict...

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