Trent Mick's Win64 changes: size_t vs. int or long; also some overflow
tests.
diff --git a/Python/ceval.c b/Python/ceval.c
index 78196ba..e153432 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -2876,7 +2876,7 @@
 	}
 	else {
 		char *s = PyString_AsString(prog);
-		if ((int)strlen(s) != PyString_Size(prog)) {
+		if (strlen(s) != (size_t)PyString_Size(prog)) {
 			PyErr_SetString(PyExc_ValueError,
 					"embedded '\\0' in exec string");
 			return -1;