incomplete declarations here any more. Some things depend on
incomplete declarations elsewhere. The `offset' arg to d_mmap_t is
bogus (it is `int' but should be `vm_offset_t') but it is what the
driver mmap functions actually accept, although they are passed a
`vm_offset_t'.
Function declararions in headers should always be complete to avoid
warnings from `gcc -Wstrict-prototypes' for compiling modules that
don't even use the offending declarations.