When building with CMake, enabling LibreSSL will link both tls and crypto (see here); however, when building with Autotools, CheckSSL.m4 relies on pkg-config to return libraries to link (here).

While OpenSSL's package info reports both ssl and crypto for linking, LibreSSL's tls package only reports tls. Solving this would require also running PKG_CHECK_MODULES() for libcrypto.

I don't expect this to be resolved in light of CDRIVER-1349, but I did want to open a ticket for posterity.