Fixed m_ssl_gnutls build on Windows; gnutls.h uses ssize_t which is defined in gcrypt.h
Fix property list arguments.
Fix errors in socketengine_ports so it compiles on Solaris

Thanks to fraggeln for reporting and testing
m_ldapoper Fix typo spotted by @lordsith49

Fixes #392
OpenBSD does not have KERN_MAXFILESPERPROC.
Fix the poll socket engine on BSD's other than FreeBSD.
Include <list> in base.h to prevent build errors on OpenBSD.
Replace a GNUmake idiom with the portable equivalent.
m_banredirect Remove unnecessary hooks, cleanup

- Remove prioritization before m_banexception, it doesn't even hook OnUserPreJoin
- Remove OnChannelDelete handler: nothing to do in that case, our extension item is automatically freed
- Remove empty OnRehash handler
m_banredirect Deny the join to the redirect channel if it has a redirecting ban set that matches the user

Fixes #395 reported by @patatje368
m_messageflood Ask to be the last to handle OnUserPreMessage/OnUserPreNotice

Fixes #394 reported by @JDowny
cmode_b: Correction to the maxbans conditional
It was possible to set one more ban beyond the configured limit.
Merge pull request #397 from Robby-/insp20+cmode_b-limit

[2.0] cmode_b: Correction to the maxbans conditional
m_maphide Ignore unregistered users

Fixes #400 reported by @SaberUK
m_spanningtree Fix rare desync when a KILL crosses a message that has the killed user's prefix and modifies global state
Fix warning: "const type qualifier on return type has no effect".
Merge pull request #403 from SaberUK/insp20+wextra-fixes

Fix warning: "const type qualifier on return type has no effect".
Fix OpenSSL detection on distributions which modify the version number.
Merge pull request #407 from SaberUK/insp20+fix-openssl-detection

Fix OpenSSL detection on distributions which modify the version number.
Use GNU install on Solaris.