PostgreSQL support in update scripts

I did not tested following codes. Just copied and pasted from system.install file.

$ret[] = update_sql("ALTER TABLE {feedapi} ADD skip SMALLINT NOT NULL DEFAULT '0'");

can be implemented as

db_add_column($ret, 'feedapi', 'skip', 'smallint', array('not null' => TRUE, 'default' => 0));

and

 $ret[] = update_sql("ALTER TABLE {feedapi} 
        ALTER COLUMN url TYPE text,
        ALTER COLUMN link TYPE text");

can be implemented as

 db_change_column($ret, 'feedapi', 'url', 'url', 'text', array('default' => "", 'not null' => TRUE));
db_change_column($ret, 'feedapi', 'link', 'link', 'text', array('default' => "", 'not null' => TRUE));

Well, what is the version of the postgresql that you use?
I tested all of my install scripts with this:

[aaron@vonat ~]$ psql --version
psql (PostgreSQL) 8.2.7

I read at the http://drupal.org/requirements page that i should rely on "PostgreSQL 7.4 or higher".

Narno:
I committed what mustafau suggested. Please try it out and if you still experience nonsense, please reopen the ticket.