pg_restore --single-transaction and --clean

As another glitch in pg_restore, a combination of options
--single-transaction and --clean raises errors if we restore data
into an empty database. The reason is pg_restore uses DROP <OBJECT>.
The cleanup command fails if the target object doesn't exist.

Is it a TODO item to replace "DROP" into "DROP IF EXISTS"
for cleanup commands in pg_restore?

Regards,
---
Takahiro Itagaki
NTT Open Source Software Center