systemc: Don't depend on the order of static initializers.

STL containers may need to be constructed before they're used. Don't
count on being able to insert into them during a static initializer.

Change-Id: Icb05d5084a470e1ebd976ae6e1954b1a78aabd6a
Reviewed-on: https://gem5-review.googlesource.com/c/13329
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

src/systemc/core/python.hh

@@ -37,6 +37,8 @@ namespace sc_gem5
 
 struct PythonReadyFunc
 {
+    PythonReadyFunc *next;
+
     PythonReadyFunc();
     ~PythonReadyFunc() {}
     virtual void run() = 0;
@@ -44,6 +46,8 @@ struct PythonReadyFunc
 
 struct PythonInitFunc
 {
+    PythonInitFunc *next;
+
     PythonInitFunc();
     ~PythonInitFunc() {}
     virtual void run(pybind11::module &systemc) = 0;