pgsql-server: Still another try at matching system timezone nicely.

Log Message:
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Still another try at matching system timezone nicely. On non-Windows
machines, break tie scores by preferring shorter zone names over longer;
for names of equal length, prefer the alphabetically first name. This
yields for example 'EST5EDT' not 'America/New_York' for US eastern time.
On Windows, abandon the whole concept of inspecting the detailed behavior
of the system TZ library, because it doesn't bear inspection :-(. Instead
use a hardwired mapping table to select our zone name based on the
result of strftime %Z output. Windows code from Magnus Hagander.

Modified Files:
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pgsql-server/src/timezone:
pgtz.c (r1.20 -> r1.21)
(http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/timezone/pgtz.c.diff?r1=1.20&r2=1.21)