Attached are two options for doing that. One overrides bytea_output locally where-ever needed, and the other overrides it for the entire 'regression' database.
The solution that overrides bytea_output locally looks appropriate. It may not be required to change the format for entire database.
Had there been a way to convert bytea_output from 'hex' to 'escape' internally, that could have simplified this customization even more.
Well, the conversion from 'hex' to 'escape' is available using the function encode().
So the queries that are failing due to the setting bytea_output = escape, can be wrapped under encode(), to obtain the result in 'escape' format.
Here is another way to resolve the same problem. The patch is attached.
