Make sure that marshal and pickle continue to output 17

digits of precision for floats.

Modules/_pickle.c

@@ -1025,7 +1025,7 @@ save_float(PicklerObject *self, PyObject *obj)
         if (pickler_write(self, &op, 1) < 0)
             goto done;
 
-        buf = PyOS_double_to_string(x, 'r', 0, 0, NULL);
+        buf = PyOS_double_to_string(x, 'g', 17, 0, NULL);
         if (!buf) {
             PyErr_NoMemory();
             goto done;

Python/marshal.c

@@ -237,7 +237,7 @@ w_object(PyObject *v, WFILE *p)
 		}
 		else {
 			char *buf = PyOS_double_to_string(PyFloat_AS_DOUBLE(v),
-                                                          'r', 0, 0, NULL);
+                                                          'g', 17, 0, NULL);
 			if (!buf)
                             return;
 			n = strlen(buf);
@@ -269,7 +269,7 @@ w_object(PyObject *v, WFILE *p)
 			char *buf;
 			w_byte(TYPE_COMPLEX, p);
 			buf = PyOS_double_to_string(PyComplex_RealAsDouble(v),
-                                                    'r', 0, 0, NULL);
+                                                    'g', 17, 0, NULL);
 			if (!buf)
                             return;
 			n = strlen(buf);
@@ -277,7 +277,7 @@ w_object(PyObject *v, WFILE *p)
 			w_string(buf, (int)n, p);
 			PyMem_Free(buf);
 			buf = PyOS_double_to_string(PyComplex_ImagAsDouble(v),
-                                                    'r', 0, 0, NULL);
+                                                    'g', 17, 0, NULL);
 			if (!buf)
                             return;
 			n = strlen(buf);