This is pretty straight forward stuff people. I work for a major Asian carrier and this is what our Ops manual states:
Departure and Climb
Departure Tracking
If a SID or Departure Clearance specifies ‘Maintain Runway Heading’ it is implied that a drift correction will be applied in order to maintain the runway track.
Exceptions - USA, Canada and Australia require that “Runway Heading” be maintained without drift correction.
In other words in Australia, USA and Canada you fly a heading that corresponds to the runway track derived from the relevant Jepp or Dap chart. All the other countries you fly a heading that gives you the required runway track, i.e. allowing for drift.