Fixes committed.
- Thomas
Fix up "Postgres-style" time interval representation when fields havemixed-signs. Previous effort left way too many
minussigns, and was atleast as broken as the one before that :(
Clean up "ISO-style" time interval representation to omit zero fields ifthere is at least one non-zero field. Supress
someleading plus signswhen not necessary for clarity.
Replace every #ifdef __CYGWIN__ block with a cleaner TIMEZONE_GLOBAL
macrodefined in datetime.h.