Things differ between airports. At Cairo with its 3 parallel runways, the clearance is typically for runway heading, 6000ft, contact radar. So heading it is and let ATC sort out the drift. Other airports, like the slightly more mountaineous Tehran (29R/L with L being a secondary taxiway in practice most of the times) require runway track and there even is a corresponding SID: IKA1A reads "Fly runway track, climb 7000ft, contact radar when airborne and expect vectors". No need to overthink it - the clearance is given, confirmed, accepted by the Captain, and will be flown.
For those advocating flying a track when cleared a heading: what do You do when instructed by London approach to e. g. leave Lambourne on heading 265? Will You fly the cleared heading then or will You introduce a wind correction on Your own and deviate from Your clearance? If You follow the clearance in this case and fly the heading, letting ATC sort out the separation, what makes the heading when airborne different?