Log Message:
-----------
The recent patch to log changes in postgresql.conf settings dumped core
if the initial value of a string variable was NULL, which is entirely
possible. Noted while experimenting with custom_variable_classes.
Modified Files:
--------------
pgsql/src/backend/utils/misc:
guc-file.l (r1.62 -> r1.63)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/misc/guc-file.l?r1=1.62&r2=1.63)