Fix new compiler warnings. Unused var in compile.c. Argsize mismatches

in binascii.c (only on platforms with signed chars -- although Py_CHARMASK
is documented as returning an int, it only does so on platforms with
signed chars).

Modules/binascii.c

@@ -918,7 +918,7 @@ This function is also available as \"hexlify()\".";
 
 
 static int
-to_int(char c) 
+to_int(int c) 
 {
 	if (isdigit(c))
 		return c - '0';

Python/compile.c

@@ -305,7 +305,6 @@ com_error(struct compiling *c, PyObject *exc, char *msg)
 {
 	size_t n = strlen(msg);
 	PyObject *v, *tb, *tmp;
-	char *s;
 	c->c_errors++;
 	if (c->c_lineno <= 1) {
 		/* Unknown line number or single interactive command */