systemc: Add the nonstandard macro SC_NEW.

This is in the Accellera implementation and in the regression tests.
The implementation here is a bit different than theirs in that it uses
std::unique_ptrs.

Change-Id: Id3d1ad82482b94a5d99f27e02d1e447ca1944797
Reviewed-on: https://gem5-review.googlesource.com/11255
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

src/systemc/core/sc_module.cc

@@ -27,6 +27,9 @@
  * Authors: Gabe Black
  */
 
+#include <memory>
+#include <vector>
+
 #include "base/logging.hh"
 #include "systemc/ext/core/sc_module.hh"
 
@@ -539,4 +542,12 @@ sc_end_of_simulation_invoked()
     return false;
 }
 
+sc_module *
+sc_module_sc_new(sc_module *mod)
+{
+    static std::vector<std::unique_ptr<sc_module> > modules;
+    modules.emplace_back(mod);
+    return mod;
+}
+
 } // namespace sc_core