[BUG]: CI benchmark workflows cannot currently handle Cephes benchmarks

[Planeshifter]

See: stdlib-js/stdlib#2781 (comment)

Time estimate without AI: 2h.
Time estimate with AI: 1h 45min.

[Planeshifter]

PR-URL: stdlib-js/stdlib#5378

[Planeshifter]

Time to completion: 40min.

Time after initial PR: 0min.

[Planeshifter]

Notes: Main time spent was reproducing the problem locally; fix is simply to install the missing dependency in the C benchmark workflow, which was done quickly.