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().

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

 in DecodeTimeOnly(). Only present when seconds are not specified
 for input.

Rename date+time conversion to datetime to ensure less than 16 characters
 in routine name (required to fit in pg_proc table).

Before, char16 was missing last character for output.

Allow true/false, yes/no, 1/0. Throw elog warning if anything else.
Allow shorter strings, so "t", "tr", "tru" and "true" match "true".
Old behavior accepted anything starting with "t" as TRUE,
 everything else as FALSE.

Leave all other input values to return FALSE.
In next version, do more checking for valid inputs for both TRUE and FALSE.

 rather than just 't' and 'T'.  This allows yes/no and 1/0
 to be interpreted as one might expect.
Clean up function declarations to use bool as the type for arguments
 and return values.