うちの環境だと

# Homebrew版
ccl-dev❦: nm /usr/local/opt/openssl/lib/libssl.dylib | grep SSL_get_peer_certificate
0000000000018d23 T _SSL_get_peer_certificate

# system default 版
ccl-dev❦: nm /usr/lib/libssl.dylib | grep SSL_get_peer_certificate
0000000000037290 T _SSL_get_peer_certificate

>>899 そちらで
nm /usr/local/lib/libssl.dylib | grep SSL_get_peer_certificate
を叩くとどう出ます？