use [=] capture default specification where possible Files affected: Canvas.cc, GLCanvas.cc, file-editor-tab.cc, file-editor.cc, octave-qscintilla.cc, main-window.cc, octave-qobject.cc, set-path-model.cc, variable-editor-model.cc, workspace-view.cc, call-stack.cc, graphics.cc, input.cc, interpreter.cc, load-path.cc, pr-output.cc, strfns.cc, sysdep.cc, audiodevinfo.cc, audioread.cc, convhulln.cc, oct-parse.yy, pt-eval.cc, lo-sysdep.cc, oct-glob.cc, oct-string.cc, and url-transfer.cc.

--- a/liboctave/system/lo-sysdep.cc	Fri Oct 02 12:58:12 2020 -0400
+++ b/liboctave/system/lo-sysdep.cc	Fri Oct 02 13:25:00 2020 -0400
@@ -221,7 +221,8 @@
           return false;
         }
 
-      unwind_action act ([fptr, tmpname] () {
+      unwind_action act ([=] ()
+                         {
                            std::fclose (fptr);
                            sys::unlink (tmpname);
                          });