improve-test-perl-README.patch

diff --git a/src/test/perl/README b/src/test/perl/README
index bfc7cdcfa3..94b00096fb 100644
--- a/src/test/perl/README
+++ b/src/test/perl/README
@@ -70,20 +70,15 @@ perldoc for the test modules, e.g.:
 
     perldoc src/test/perl/PostgresNode.pm
 
-Required Perl
--------------
-
-Tests must run on perl 5.8.3 and newer. perlbrew is a good way to obtain such
-a Perl; see http://perlbrew.pl .
-
-Just install and
-
-    perlbrew --force install 5.8.3
-    perlbrew use 5.8.3
-    perlbrew install-cpanm
-    cpanm install IPC::Run
-
-then re-run configure to ensure the correct Perl is used when running
-tests. To verify that the right Perl was found:
-
-    grep ^PERL= config.log
+Portability
+-----------
+
+Avoid using any bleeding-edge Perl features.  We have buildfarm animals
+running Perl versions as old as 5.8.3, so your tests will be expected
+to pass on that.
+
+Also, do not use any non-core Perl modules except IPC::Run.  Or, if you
+must do so for a particular test, arrange to skip the test when the needed
+module isn't present.  If unsure, you can consult Module::CoreList to find
+out whether a given module is part of the Perl core, and which module
+versions shipped with which Perl releases.