Change declarations from "struct varlena *" to "text *".
Remove register variables since compiler should do better on its own.

 names over 16 characters. datet_datetime() -> datetime_datetime(), etc.

some of the ports...

Makefile.global.

End result, if all goes well, should allow for much easier porting, since
there will no longer be a concept of a "port".  Most, if not everything,
*should* be determined by configure, or by the compiler itself.  Still
work to be done though :)

Define an "ISO-style" timespan output format with "hh:mm:ss" fields.
 Enabled by DateStyle = USE_ISO_DATES.

 Probably have it wrong (dd.mm/yyyy) but can change it when we know.
 Input routines always handled it.

 hardcoded values.

Check valid numeric input more carefully for delta times.
Implement day of year as possible input to datetime_part().

From: Bryan Henderson <bryanh@giraffe.netgate.net>

The attached patch makes elog() write the message to stderr if there is
no frontend to talk to.

Add istrue() and isfalse() routines to implement SQL3 IS TRUE and IS FALSE.