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, 1 insertions, 1 deletions

diff --git a/Objects/structseq.c b/Objects/structseq.c
index 603477f594..ac3cf03d45 100644
--- a/Objects/structseq.c
+++ b/Objects/structseq.c
@@ -97,7 +97,7 @@ structseq_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
 	PyObject *ob;
 	PyStructSequence *res = NULL;
 	int len, min_len, max_len, i, n_unnamed_fields;
-	static char *kwlist[] = {"sequence", "dict", 0};
+	static const char *kwlist[] = {"sequence", "dict", 0};
 
 	if (!PyArg_ParseTupleAndKeywords(args, kwds, "O|O:structseq", 
 					 kwlist, &arg, &dict))