SSL_load_error_stringsもエラー文字列を読み込む関数だが、ERR_load_BIO_stringsとはちょっと違う模様。
/docs/man1.0.2/crypto/SSL_load_error_strings.html
SSL_load_error_strings.cで、
ERR_load_BIO_stringsに加えて、SSL_load_error_stringsも呼ぶ。
$ vi SSL_load_error_strings.c
$ gcc -o SSL_load_error_strings SSL_load_error_strings.c -lssl -lcrypto
$ ./SSL_load_error_strings ctx = 00972ad0
SSL_CTX_load_verify_locations error!
139907107936152:error:02001002:system library:fopen:No such file or directory:bss_file.c:175:fopen('dummyurl','r')
139907107936152:error:2006D080:BIO routines:BIO_new_file:no such file:bss_file.c:182:
139907107936152:error:0B084002:x509 certificate routines:X509_load_cert_crl_file:system lib:by_file.c:258:
$func(132)がX509_load_cert_crl_fileなのがわかった。
