[Simh] Compile fail, linux 64 bit vax780 target

[Paul Koning]

> On May 8, 2020, at 7:38 AM, Mark Wickens <mark at wickensonline.co.uk> wrote:
> 
> I'm getting an error  - undeclared type off64_t when I try and compile the vax780 emulator from a clone of the git repository made today. If I edit sim_fio.c and change off64_t to __off64_t I then get implicit declaration warnings for fopen64, fseeko64 and ftello64 and the Hardware Core Test EVKAA core dumps.

Strange.  What gcc version?  64 bit support has been a core part of gcc for ages.

	paul