[tz] Question about bug seen in OpenBSD and FreeBSD related to tzname

[Paul Eggert]

On 11/20/19 11:19 PM, Andras Farkas wrote:
> I couldn't get things to
> compile while using -DUSG_COMPAT=1 in CFLAGS, on FreeBSD.  However, I
> was able to get things to compile like that on OpenBSD.  (Notably,
> FreeBSD doesn't support daylight or timezone, itself, while OpenBSD
> does.  This seems to indicate USG_COMPAT'd tzcode can only be compiled
> on OSes already supporting those features)

What happens if you compile with -DHAVE_POSIX_DECLS=0? Arguably it 
should be set that way if FreeBSD does not declare the POSIX-required 
'daylight' and 'timezone'.

I see now that POSIX marks 'daylight' and 'timezone' with "XSI", meaning 
it's optional and present only if the X/Open Systems Interfaces option 
is supported, so perhaps tzcode should have a different macro for 
identifiers that are XSI rather than core POSIX.