Multiple component primary keys are exported wrong

[francois]

Create a table, add two fields, mark both as PRIMARY KEY. Export as Postgres. This is what's generated:

CREATE TABLE a(
  f1 int PRIMARY KEY,
  f2 int PRIMARY KEY
);

This is what's desired:

CREATE TABLE a(
  f1 int,
  f2 int,
  PRIMARY KEY(f1, f2)
);