Hello!
  I think, finally, that the simplest way to solve this would be patch
configure, not datetime.c, dt.c and all that.  The struct tm on linux has tm_gmtoff and tm_zone, so it will be enough
if postgres' configure undefine HAVE_TZSET and HAVE_INT_TIMEZONE on glibc2.
  Python's configure.in has the following:
# checks for structures
AC_HEADER_TIME
AC_STRUCT_TM
AC_STRUCT_TIMEZONE  and this do all neccessary defines. I think postgres' configure will
require some more tricks.
  Continue investigating...
Oleg.
----  Oleg Broytmann     http://members.tripod.com/~phd2/     phd2@earthling.net          Programmers don't die, they
justGOSUB without RETURN.