llvm-project

c2a0350d - [libc++] Simplify a few places where we use __index_sequence (#167213)

[libc++] Simplify a few places where we use __index_sequence (#167213) This is done in two ways: 1) `index_sequence_for` is back-ported as `__index_sequence_for` 2) Extra functions just to expand the parameter pack are replaced with lambdas