pgsql: Teach autovacuum how to determine whether a temp table belongs to

Log Message:
-----------
Teach autovacuum how to determine whether a temp table belongs to a crashed
backend. If so, send a LOG message to the postmaster log, and if the table
is beyond the vacuum-for-wraparound horizon, forcibly drop it. Per recent
discussions. Perhaps we ought to back-patch this, but it probably needs
to age a bit in HEAD first.

Modified Files:
--------------
pgsql/src/backend/catalog:
namespace.c (r1.106 -> r1.107)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/catalog/namespace.c?r1=1.106&r2=1.107)
pgsql/src/backend/postmaster:
autovacuum.c (r1.79 -> r1.80)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/postmaster/autovacuum.c?r1=1.79&r2=1.80)
pgsql/src/backend/storage/ipc:
sinvaladt.c (r1.72 -> r1.73)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/storage/ipc/sinvaladt.c?r1=1.72&r2=1.73)
pgsql/src/include/catalog:
namespace.h (r1.53 -> r1.54)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/namespace.h?r1=1.53&r2=1.54)
pgsql/src/include/storage:
sinvaladt.h (r1.48 -> r1.49)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/storage/sinvaladt.h?r1=1.48&r2=1.49)