Log Message:
www/squid4: update to 4.12

Update squid4 to 4.12 (Squid 4.12).  This release includes fix for
CVE-2020-14058:   <http://www.squid-cache.org/Advisories/SQUID-2020_6.txt>.

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