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/complexobject.c b/Objects/complexobject.c
index 138ba80..08c8c89 100644
--- a/Objects/complexobject.c
+++ b/Objects/complexobject.c
@@ -829,7 +829,7 @@ complex_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
 	Py_complex cr, ci;
 	int own_r = 0;
 	static PyObject *complexstr;
-	static char *kwlist[] = {"real", "imag", 0};
+	static const char *kwlist[] = {"real", "imag", 0};
 
 	r = Py_False;
 	i = NULL;