- Don't use process-shared semaphores unless multiple workers are used;
OpenBSD's semaphore implementation doesn't support them.
- Default to using a single worker on OpenBSD, so that extra flags aren't
needed to allow ualpn to work.
uacme is a lightweight client for the RFC8555 ACMEv2 protocol used with
certificate authorities to validate and issue X509 certificates. It is
written in plain C with minimal dependencies (libcurl and one of GnuTLS,
OpenSSL or mbedTLS) and can handle all authentication types via external
hooks (examples for http-01, dns-01 via nsupdate, and tls-alpn-01).
