On NetBSD/amd64, gcc warns that strlen() is
incompatible with the builtin strlen's type.

Presumably, this is because strlen is declared
as size_t.  What's the appropriate fix for this?
Adding -fno-builtin-strlen is easy enough. :)

This brings me to another point: I think it would
be a good idea to have a generic way for packages
to detect whether or not they're running on a
64-bit platform, as .if statements checking
for every possibility are cumbersome.  There's
${ABI}, but that's not set except in certain cases.
Could we extend it?

Regards,

--Blair