[libsigcplusplus] signal_exec: =delete copy and move operations.

[Murray Cumming <murrayc src gnome org>]

commit aab6603733c971e3e68e6c29680c753e14ad27ee
Author: Murray Cumming <murrayc murrayc com>
Date:   Fri Apr 15 08:50:59 2016 +0200

    signal_exec: =delete copy and move operations.

 sigc++/signal_base.h |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)
---
diff --git a/sigc++/signal_base.h b/sigc++/signal_base.h
index c9d3172..d393a5b 100644
--- a/sigc++/signal_base.h
+++ b/sigc++/signal_base.h
@@ -206,6 +206,12 @@ struct SIGC_API signal_exec
     sig_->reference_exec();
   }
 
+  signal_exec(const signal_exec& src) = delete;
+  signal_exec operator=(const signal_exec& src) = delete;
+
+  signal_exec(signal_exec&& src) = delete;
+  signal_exec operator=(signal_exec&& src) = delete;
+
   /// Decrements the reference and execution counter of the parent sigc::signal_impl object.
   inline ~signal_exec() { sig_->unreference_exec(); }