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/ext/core/sc_module.hh

@@ -244,6 +244,12 @@ typedef sc_module sc_channel;
 bool sc_start_of_simulation_invoked();
 bool sc_end_of_simulation_invoked();
 
+// Nonstandard
+// Allocates a module of type x and records a pointer to it so that it gets
+// destructed automatically at the end of the simulation.
+sc_module *sc_module_sc_new(sc_module *);
+#define SC_NEW(x) ::sc_core::sc_module_sc_new(new x);
+
 } // namespace sc_core
 
 #endif  //__SYSTEMC_EXT_CORE_SC_MODULE_HH__