Build fix: include errno.h in menu.cpp, which uses errno.
Import "+support for SDD1 Emu added (GraphicPack not needed anymore!!)".

This commit is based on https://github.com/dmitrysmagin/snes9x4d-rzx50/commit/c1b5ea12c53c0c3b1ae083f7e999b8c6c7e010bd but includes only the code relevant to S-DD1 decompression chip emulation.