Fix forward search

The provided working directory was not properly set when the underlying
process starts.
It is not clear, why only this one call to one.startscript()
needs fixing. OTOH, the other calls do not use 'Systemcall::DontWait'
as the first parameter.

src/frontends/qt/GuiView.cpp

@@ -4496,7 +4496,7 @@ void GuiView::dispatch(FuncRequest const & cmd, DispatchResult & dr)
 			command = subst(command, "$$t", texname);
 			command = subst(command, "$$o", outname);
 
-			PathChanger p(path);
+			volatile PathChanger p(path);
 			Systemcall one;
 			one.startscript(Systemcall::DontWait, command);
 			break;