NEW: devel/z80ex

Hi ports --

Attached is a new port, devel/z80ex. Z80ex is a portable ZiLOG Z80
CPU emulation library.

---
pkg/DESCR:
Z80~Ex is the portable ZiLOG Z80 CPU emulator designed as a library.
Goals include precise opcode emulation (documented & undocumented),
exact timings for each opcode (including I/O operations), multiple CPU
contexts. A disassembler is also included.
---

Builds on amd64 and sparc64. Required for a port of the cowgol
language suite.

OK?

~Brian