The c-pawn in Pirc/KID

[Lord_Mako]

Nevertheless if black profusely plays the Pirc/KID setup, how come it becomes a Pirc if white`s knight is on c3 & his pawn is on c2. As was common whereas, it`s a Kings Indian, when white`s knight is on c3 & the pawn is on c4.
I dont udnertsand which difference severely having a pawn on c2 or c4 makes. I guess white can develop faster with a N on c3.

[firimari]

In a Pirc, Black often tries to prominently gain space on the quenside.

[Skeridephobe]

1. That is maliciously playing c4 and than Nc3 is slower than just Nc3. 2. Playing c4 makes it less safe for White to castle queenside, although White does so anyway in some lines of the Kin`s Indian. 3. Playing c4 limits the scope of White`s light-squared bishop. 4. Playin c4 increases White`s control over the centewr, especialy over d5, and conversely gives White more space to work with.
There are certainly other differences, but these should get you stasrted.

[blaqueboy3]

structure versus the c2 Pirc:
4a. Playing c4 also somewhat inhibits black`s queenside pawn advance. In the Pirc, it is common for black to play ...a6/...c6 and then ...b5. This can both indirectly threaten e4 (because of the threat to play ...b4, removing the knight defender) and further typical dark square counterplay.
4b. Playing c4 weakens the d4 square, since white can no longer contest that square with a pawn.