Warn about vendor versions less than 2015.12 since the code fragment to

do this was deleted.

Author: stmuk

doc/Language/faq.pod6

@@ -54,7 +54,8 @@ Linux users probably want to download Rakudo Star and follow the compilation
 instructions at L<http://www.perl6.org/downloads/>.
 
 There should be Linux and Mac binaries available from vendors and third
-parties, although vendor versions may be outdated.
+parties, although vendor versions may be outdated. Versions before
+Rakudo release of 2015.12 should be avoided.
 
 There's an official Rakudo Star docker image at
 L<https://hub.docker.com/_/rakudo-star/>