OpenSSL plugin does not compile with OpenSSL 1.1.x on Debian 10 (buster)

[bma67]

gcc is version 8.3.0

Error is:

plugins/fitsec_openssl.c: In function 'OpenSSL_ReadSignature':
plugins/fitsec_openssl.c:246:21: error: dereferencing pointer to incomplete type 'ECDSA_SIG' {aka 'struct ECDSA_SIG_st'}
BN_bin2bn(s, 32, sg->s);

[bma67]

Attached, you will find a proposed patch.
FITSec_OpenSSL_v1.1.x.patch.txt