Because that's the variable actually used by CPack.

fix position of assert expected/actual parameter

`has()` only tests for an argument presence which is always true for
arguments with default values. Use `get<bool>()` to check the value
instead.

and not consider its value. treat arguments with a set default value as
present.

`A || !A` is `true` so write `(A && B) || !A` as `B || !A`

Disables TLS copy constructor and operator, as they can lead to errors and reservation of too much keys in TLS storage;

gather method was added to TLS to gather data from all threads;