Allowing line-continuation in pgbench custom scripts

Hi,

In a custom pgbench script, it seems convenient to be able to split a
really long query to span multiple lines using an escape character
(bash-style). Attached adds that capability to read_line_from_file()
in pgbench.c

For example,

BEGIN;
\setrandom 1 16500000
UPDATE table \
SET col2 = (clock_timestamp() + '10s'::interval * random() * 1000), \
col3 = (clock_timestamp() + '10s'::interval * sin(random() *
(2*pi()) ) * 1000) \
WHERE col1 = :id;
COMMIT;

instead of:

BEGIN;
\setrandom id 1 16500000
UPDATE table SET col2 = (clock_timestamp() + '10s'::interval *
random() * :id), col3 = (clock_timestamp() + '10s'::interval *
sin(random() * (2*pi()) ) * 100000) WHERE col1 = :id;
COMMIT;

Thoughts?

--
Amit