[libc] Add spec/*.td as dependencies to add_gen_header

Summary: It also re formats long lines in `add_gen_header`

Reviewers: sivachandra

Reviewed By: sivachandra

Subscribers: mgorny, tschuett, libc-commits

Differential Revision: https://reviews.llvm.org/D78349

GitOrigin-RevId: d9e96b6a026777d299e12d3a50d00c2308d4dcdf
1 file changed