threads.xs: don't Copy() null pointer
authorDavid Mitchell <davem@iabyn.com>
Mon, 4 Sep 2017 08:54:58 +0000 (09:54 +0100)
committerDavid Mitchell <davem@iabyn.com>
Mon, 4 Sep 2017 10:09:06 +0000 (11:09 +0100)
commit97fcda75b598695644a4ad496e090941f5b7dcbc
treec5519547d67620ee702238279a838a29b4638cb4
parentf6107ca24b4cf22dcf7fd69d65612ad718c48fca
threads.xs: don't Copy() null pointer

If a thread is created with no parameters, e.g.

    use threads;
    threads->new(sub {})->join;

Then it tries to Copy() zero parameters to AvARRAY(params), which is null.
Since v5.27.3-31-gf14cf36, this triggers an assert failure, so threaded
builds have been badly broken.
dist/threads/lib/threads.pm
dist/threads/threads.xs