Mask warning from IPC init block.

The init block was added to help solve some problems when using IPC. It
is not critical that it run, specially when someone does something
clever, which is the usual cause of the warning.

See https://rt.perl.org/Ticket/Display.html?id=133382

Changes

@@ -1,5 +1,7 @@
 {{$NEXT}}
 
+    - Mask warning from the recent IPC fix generated when threaded Test tools are loaded at run-time
+
 1.302138  2018-07-11 09:29:51-07:00 America/Los_Angeles
 
     - No changes since trial

lib/Test2/IPC.pm

@@ -19,7 +19,14 @@ use Test2::API qw{
 };
 
 # Make sure stuff is finalized before anyone tried to fork or start a new thread.
-INIT { context()->release() }
+{
+    # Avoid warnings if things are loaded at run-time
+    no warnings 'void';
+    INIT {
+        use warnings 'void';
+        context()->release();
+    }
+}
 
 use Carp qw/confess/;
 

t/Legacy_And_Test2/thread_init_warning.t

@@ -0,0 +1,22 @@
+use strict;
+use warnings;
+
+use Test2::Util qw/CAN_THREAD/;
+BEGIN {
+    unless(CAN_THREAD) {
+        require Test::More;
+        Test::More->import(skip_all => "threads are not supported");
+    }
+}
+
+use threads;
+
+my @warns;
+{
+    local $SIG{__WARN__} = sub { push @warns => @_ };
+    require Test::More;
+}
+
+Test::More::is_deeply(\@warns, [], "No init warning");
+
+Test::More::done_testing();