[lint] Allow std::variant to appear in codebase.
Summary
All of the compilers and libraries we now target support this C++17 language feature. The last holdout was our macOS support, but since we upgraded to 10.14 as the base deployment target in MR !1524 (merged), std::variant is now supported on macOS as well. As such, we can remove this linting check from our codebase.
Test Plan
ninja check-lint-lint-cpp
- (Optional) Add some code that uses
std::variant
in the codebase into your working dir and doninja check-lint-lint-cpp
and it should not complain about that.