Comment 15 for bug 1246802

Yes, I didn't trace all the members which call __unguarded_partition_pivot.

The better (in my opinion) fix is to change __introselect from:

__last - __first > 3

to:

__last - __first > int(_S_threshold)

Like the other call the __unguarded_partition_pivot.

I am currently testing that change.

The 'last - 2' was on purpose (although, it is causing the problem!), as 'last - 1' is the the last element of the array which we want to avoid (think of it as 'last - 1 - 1', to go with 'first + 1'. Obviously we couldn't de-ref 'last - 1'.