Add PYTHON_API_STRING, which is PYTHON_API_VERSION as a string literal.

Under Windows, add MS_DLL_ID and MS_DLL_VERSION_ID for Mark H.

Independent change: if Py_TRACE_REFS is defined, rename Py_InitModule4
so so linking with incompatible modules will create a link time error.

[Backing out of previous changes (also for modsupport.c) to test
the latter at runtime.]

Include/modsupport.h

@@ -53,6 +53,7 @@ extern int PyArg_VaParse Py_PROTO((PyObject *, char *, va_list));
 extern PyObject *Py_VaBuildValue Py_PROTO((char *, va_list));
 
 #define PYTHON_API_VERSION 1005
+#define PYTHON_API_STRING "1005"
 /* The API version is maintained (independently from the Python version)
    so we can detect mismatches between the interpreter and dynamically
    loaded modules.  These are diagnosticised by an error message but
@@ -60,6 +61,9 @@ extern PyObject *Py_VaBuildValue Py_PROTO((char *, va_list));
    after loading the module).  The error message is intended to
    explain the core dump a few seconds later.
 
+   The symbol PYTHON_API_STRING defines the same value as a string
+   literal.  *** PLEASE MAKE SURE THE DEFINITIONS MATCH. ***
+
    Please add a line or two to the top of this log for each API
    version change:
 
@@ -74,6 +78,24 @@ extern PyObject *Py_VaBuildValue Py_PROTO((char *, va_list));
    9-Jan-1995	GvR	Initial version (incompatible with older API)
 */
 
+#ifdef MS_WINDOWS
+/* Special defines for Windows versions.  MS_DLL_ID is the key
+   used in the registry.
+   The full MS_DLL_VERSION_ID is imbedded in the core DLL, and
+   is so installers can determine incremental changes.
+*/
+#define MS_DLL_ID "1.4.0"
+#define MS_DLL_VERSION_ID       MS_DLL_ID "." PYTHON_API_STRING
+
+#endif /* MS_WINDOWS */
+
+#ifdef Py_TRACE_REFS
+/* When we are tracing reference counts, rename Py_InitModule4 so
+   modules compiled with incompatible settings will generate a
+   link-time error. */
+#define Py_InitModule4 Py_InitModule4TraceRefs
+#endif
+
 extern PyObject *Py_InitModule4 Py_PROTO((char *, PyMethodDef *,
 					  char *, PyObject *, int));
 #define Py_InitModule(name, methods) \