Add const to several API functions that take char *.

In C++, it's an error to pass a string literal to a char* function
without a const_cast().  Rather than require every C++ extension
module to put a cast around string literals, fix the API to state the
const-ness.

I focused on parts of the API where people usually pass literals:
PyArg_ParseTuple() and friends, Py_BuildValue(), PyMethodDef, the type
slots, etc.  Predictably, there were a large set of functions that
needed to be fixed as a result of these changes.  The most pervasive
change was to make the keyword args list passed to
PyArg_ParseTupleAndKewords() to be a const char *kwlist[].

One cast was required as a result of the changes:  A type object
mallocs the memory for its tp_doc slot and later frees it.
PyTypeObject says that tp_doc is const char *; but if the type was
created by type_new(), we know it is safe to cast to char *.

1 files changed, 2 insertions, 2 deletions

diff --git a/Include/import.h b/Include/import.h
index 572cb8a920..45cc6c93f2 100644
--- a/Include/import.h
+++ b/Include/import.h
@@ -12,8 +12,8 @@ PyAPI_FUNC(PyObject *) PyImport_ExecCodeModule(char *name, PyObject *co);
 PyAPI_FUNC(PyObject *) PyImport_ExecCodeModuleEx(
 	char *name, PyObject *co, char *pathname);
 PyAPI_FUNC(PyObject *) PyImport_GetModuleDict(void);
-PyAPI_FUNC(PyObject *) PyImport_AddModule(char *name);
-PyAPI_FUNC(PyObject *) PyImport_ImportModule(char *name);
+PyAPI_FUNC(PyObject *) PyImport_AddModule(const char *name);
+PyAPI_FUNC(PyObject *) PyImport_ImportModule(const char *name);
 PyAPI_FUNC(PyObject *) PyImport_ImportModuleEx(
 	char *name, PyObject *globals, PyObject *locals, PyObject *fromlist);
 PyAPI_FUNC(PyObject *) PyImport_Import(PyObject *name);