Portability of bit fields

[giomba]

Because of portability reasons, I've always avoided bit fields, and done bit masking operations by hand.

Sort of religious thought. What does even portability mean? If the compiler's implementation is coherent with itself (as it should be), does this problem even arise? I don't think we are going to link together objects produced by different compilers, or mix binaries of different architectures. We don't even need low level access to hardware registers, this is "high level" software.

Anyhow, some thoughts need to be done about:

• consequences of using bit fields in src/fdc.c
• consequences of accessing raw video memory in src/video.c