pgsql: Properly undef _(x) gettext macro.

Log Message:
-----------
Properly undef _(x) gettext macro.

Modified Files:
--------------
pgsql/src/pl/plperl:
SPI.xs (r1.12 -> r1.13)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plperl/SPI.xs.diff?r1=1.12&r2=1.13)
plperl.c (r1.68 -> r1.69)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plperl/plperl.c.diff?r1=1.68&r2=1.69)
spi_internal.c (r1.6 -> r1.7)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plperl/spi_internal.c.diff?r1=1.6&r2=1.7)
pgsql/src/timezone:
private.h (r1.10 -> r1.11)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/timezone/private.h.diff?r1=1.10&r2=1.11)