inn-2.6.0-4.fc26 fails to build in F26: checking for library containing dlopen... -ldl checking for AES_cbc_encrypt in -lcrypto... yes checking for SSL_library_init in -lssl... no configure: error: cannot find usable OpenSSL library This is caused by upgrading openssl from 1:1.0.2j-1.fc26 to 1:1.1.0b-1.fc26.
Upstream committed fixes in r9988, r10024, r10067.
The last one r10067 only adds compatibility to OpenSSL prior 0.9.8m and it requires yet another r10064 that fiddles with TLS compression options. Therefore only the first two patches are really needed for F26.