PL_linestr needs to survive until the end of scope, not just the next

FREETMPS. Fixes the underlying cause of the thread cloning SEGV
reported in http://www.nntp.perl.org/group/perl.perl5.porters/63123

p4raw-id: //depot/perl@29643

2 files changed, 10 insertions, 1 deletions

diff --git a/t/op/threads.t b/t/op/threads.t
index f699fc26df..165c542bc0 100644
--- a/t/op/threads.t
+++ b/t/op/threads.t
@@ -18,7 +18,7 @@ BEGIN {
        print "1..0 # Skip: no dynamic loading on miniperl, no threads\n";
        exit 0;
      }
-     plan(5);
+     plan(6);
 }
 use threads;
 
@@ -106,3 +106,10 @@ $SIG{__WARN__} = sub{};
 async sub {};
 print "ok";
 EOI
+
+# From a test case by Tim Bunce in
+# http://www.nntp.perl.org/group/perl.perl5.porters/63123
+fresh_perl_is(<<'EOI', 'ok', { }, 'Ensure PL_linestr can be cloned');
+use threads;
+print do 'op/threads_create.pl';
+EOI
diff --git a/t/op/threads_create.pl b/t/op/threads_create.pl
new file mode 100644
index 0000000000..34251632cf
--- /dev/null
+++ b/t/op/threads_create.pl
@@ -0,0 +1,2 @@
+threads->create( sub { } )->join;
+"ok\n";