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/Modules/cjkcodecs/multibytecodec.c b/Modules/cjkcodecs/multibytecodec.c
index 7d2d15ebfb..b0dae0c772 100644
--- a/Modules/cjkcodecs/multibytecodec.c
+++ b/Modules/cjkcodecs/multibytecodec.c
@@ -45,8 +45,8 @@ PyDoc_STRVAR(MultibyteCodec_StreamReader__doc__,
 PyDoc_STRVAR(MultibyteCodec_StreamWriter__doc__,
 "I.StreamWriter(stream[, errors]) -> StreamWriter instance");
 
-static char *codeckwarglist[] = {"input", "errors", NULL};
-static char *streamkwarglist[] = {"stream", "errors", NULL};
+static const char *codeckwarglist[] = {"input", "errors", NULL};
+static const char *streamkwarglist[] = {"stream", "errors", NULL};
 
 static PyObject *multibytecodec_encode(MultibyteCodec *,
 		MultibyteCodec_State *, const Py_UNICODE **, size_t,