Add _opcode to Windows build env

PC/config.c

@@ -66,6 +66,7 @@ extern PyObject* PyInit_atexit(void);
 extern PyObject* _PyWarnings_Init(void);
 extern PyObject* PyInit__string(void);
 extern PyObject* PyInit__stat(void);
+extern PyObject* PyInit__opcode(void);
 
 /* tools/freeze/makeconfig.py marker for additional "extern" */
 /* -- ADDMODULE MARKER 1 -- */
@@ -158,6 +159,7 @@ struct _inittab _PyImport_Inittab[] = {
     {"_pickle", PyInit__pickle},
     {"atexit", PyInit_atexit},
     {"_stat", PyInit__stat},
+    {"_opcode", PyInit__opcode},
 
     /* Sentinel */
     {0, 0}

PCbuild/pythoncore.vcxproj

@@ -524,6 +524,7 @@
     <ClCompile Include="..\Modules\mathmodule.c" />
     <ClCompile Include="..\Modules\md5module.c" />
     <ClCompile Include="..\Modules\mmapmodule.c" />
+    <ClCompile Include="..\Modules\_opcode.c" />
     <ClCompile Include="..\Modules\_operator.c" />
     <ClCompile Include="..\Modules\parsermodule.c" />
     <ClCompile Include="..\Modules\posixmodule.c" />