static unsigned outlen; /* how much data required */
static unsigned char *pending = NULL; /* any spare data */
static unsigned pendlen = 0, pendsize = 0; /* length and phys. size of buffer */
-int from_backend(void *frontend, int is_stderr, char *data, int datalen)
+int from_backend(void *frontend, int is_stderr, const char *data, int datalen)
{
unsigned char *p = (unsigned char *) data;
unsigned len = (unsigned) datalen;