[3.8] closes bpo-39630: Update pointers to string literals to be const char *. (GH-18511)

(cherry picked from commit 7386a70)

Co-authored-by: Andy Lester <andy@petdance.com>

Author: benjaminp

Objects/genobject.c

@@ -11,10 +11,10 @@ static PyObject *gen_close(PyGenObject *, PyObject *);
 static PyObject *async_gen_asend_new(PyAsyncGenObject *, PyObject *);
 static PyObject *async_gen_athrow_new(PyAsyncGenObject *, PyObject *);
 
-static char *NON_INIT_CORO_MSG = "can't send non-None value to a "
+static const char *NON_INIT_CORO_MSG = "can't send non-None value to a "
                                  "just-started coroutine";
 
-static char *ASYNC_GEN_IGNORED_EXIT_MSG =
+static const char *ASYNC_GEN_IGNORED_EXIT_MSG =
                                  "async generator ignored GeneratorExit";
 
 static inline int

Python/codecs.c

@@ -1415,7 +1415,7 @@ static PyObject *surrogateescape_errors(PyObject *self, PyObject *exc)
 static int _PyCodecRegistry_Init(void)
 {
     static struct {
-        char *name;
+        const char *name;
         PyMethodDef def;
     } methods[] =
     {

Python/errors.c

@@ -584,7 +584,7 @@ PyErr_SetFromErrnoWithFilenameObjects(PyObject *exc, PyObject *filenameObject, P
 
 #ifndef MS_WINDOWS
     if (i != 0) {
-        char *s = strerror(i);
+        const char *s = strerror(i);
         message = PyUnicode_DecodeLocale(s, "surrogateescape");
     }
     else {