Add definition for the argument_with_type_tag attribute.

This attribute originates in clang and brings support for checking types
of variadic functions' arguments for functions like fcntl() and ioctl().

Unfortunately lint(1) will complain about them: in particular as one of
the parameters is the function being tagged. For now define this attribute
in the lint-sensitive section.

Reference:
http://clang.llvm.org/docs/AttributeReference.html#type-safety-checking