Changes to squid-4.12 (05 Jun 2020):
- Regression Fix: Revert to slow search for new SMP shm pages
- Bug 5045: ext_edirectory_userip_acl is missing include files
- Bug 5041: Missing Debug::Extra breaks build on hosts with systemd
- Bug 5030: Negative responses are never cached
- HTTP: validate Content-Length value prefix
- HTTP: add flexible RFC 3986 URI encoder
- SslBump: disable OpenSSL TLSv1.3 support for older TLS traffic
- Tests: Support passing a custom config.cache to test builds
- Fix IPFilter IPv6 detection, especially on NetBSD
- Fix stall if transaction overwrites a recently active cache entry
- ... and some compile fixes