build: enable thread-safe getaddrinfo() for OpenBSD, and other tidy-ups

Aka `HAVE_GETADDRINFO_THREADSAFE`.

- enable it for OpenBSD 5.4+ (2013-11-01).
  Also adjust cmake pre-fill.

- explicitly opt-in DragonFly BSD, for 2.2.0+ (2009-02-17).
  Assuming this commit implemented this feature:
  21fcee4d6e (diff-498ff649e8770eb9a94e99a399a4b473fcea41ef58b033a2a2dae3809e17bb04)
  Prior to this patch it was enabled in autotools by accident, because
  its host ID misses `bsd` so the global BSD disable was not applied.

- autotools: fix to enable for Darwin 9+ / macOS 10.5+ (2007-10-26).
  Prior to this patch it was Darwin 6 / macOS 10.2.
  Source: https://github.com/python/cpython/issues/70112
  Ref: https://en.wikipedia.org/wiki/MacOS_version_history
  10.5 was the first one UNIX '03 certified, which requires this
  feature. iOS and others were forked from this codebase, so they also
  have support.

- cmake: add version numbers as comments.
  Sadly the OS versions are not verified. This and the autotools logic
  could possibly be implemented in `curl-setup.h` more accurately, for
  all build systems, without duplicating logic.

Also:
- cmake: `BSD` variable requires CMake 3.25+, add fallback code where
  missing.
  Ref: https://cmake.org/cmake/help/v3.25/variable/BSD.html
- unix-cache.cmake: stop listing all BSDs for `HAVE_PIPE2`,
  and fix generic BSD filter for CMake <3.25.
- unix-cache.cmake: stop listing all BSDs, since it's prefilled anyway
  for those via `OtherTests.cmake`.

Ref: https://github.com/curl/curl/pull/22138#issuecomment-4773617195

Closes #22148

CMake/unix-cache.cmake

@@ -106,14 +106,7 @@ elseif(CYGWIN OR
   set(HAVE_FSETXATTR_6 0)
 endif()
 set(HAVE_GETADDRINFO 1)
-if(CMAKE_SYSTEM_NAME STREQUAL "OpenBSD")
-  set(HAVE_GETADDRINFO_THREADSAFE 0)
-elseif(CYGWIN OR
-       CMAKE_SYSTEM_NAME STREQUAL "Linux" OR
-       CMAKE_SYSTEM_NAME STREQUAL "DragonFlyBSD" OR
-       CMAKE_SYSTEM_NAME STREQUAL "FreeBSD" OR
-       CMAKE_SYSTEM_NAME STREQUAL "MidnightBSD" OR
-       CMAKE_SYSTEM_NAME STREQUAL "NetBSD")
+if(CYGWIN)
   set(HAVE_GETADDRINFO_THREADSAFE 1)
 endif()
 set(HAVE_GETEUID 1)
@@ -219,12 +212,7 @@ if(APPLE OR
    CYGWIN)
   set(HAVE_PIPE2 0)
 elseif(CMAKE_SYSTEM_NAME STREQUAL "Linux" OR
-       BSD OR
-       CMAKE_SYSTEM_NAME STREQUAL "DragonFlyBSD" OR
-       CMAKE_SYSTEM_NAME STREQUAL "FreeBSD" OR
-       CMAKE_SYSTEM_NAME STREQUAL "MidnightBSD" OR
-       CMAKE_SYSTEM_NAME STREQUAL "NetBSD" OR
-       CMAKE_SYSTEM_NAME STREQUAL "OpenBSD" OR
+       BSD OR CMAKE_SYSTEM_NAME MATCHES "BSD" OR
        CMAKE_SYSTEM_NAME STREQUAL "SunOS")
   set(HAVE_PIPE2 1)
 endif()