pkgsrc on openbsd 6.8

[Edgar Pettijohn <edgar%pettijohn-web.com@localhost>]

Doubt its a good fix, but should help someone find the right solution. I
had to re-bootstrap with ./bootstrap --abi 64 but I also changed abi 64
to make machine_arch=amd64 instead of x86_64. After doing so I am able
to build and install packages.

I'm happy to test any real fixes.

Thanks,

Edgar