Guide to alternative expected files:

plpython_error_0.out		Python 2.4 and older

plpython_unicode.out		server encoding != SQL_ASCII and client encoding == UTF8; else ...
plpython_unicode_0.out		server encoding != SQL_ASCII and client encoding != UTF8; else ...
plpython_unicode_3.out		server encoding == SQL_ASCII

plpython_subtransaction_0.out	Python 2.5 and older (without with statement)

plpython_types_3.out		Python 3.x

Note: Building with Python 2.2 is supported, but there are no expected
files for it (too much work to maintain).
