Fixed a bug in ToCharset I introduced by fixing another one...

src/text/unicode.c

@@ -436,11 +436,12 @@ void *ToCharset(const char *charset, const char *in, size_t *outsize)
         const char *inp = in;
         char *outp = res;
         size_t inb = inlen;
-        size_t outb = outlen;
+        size_t outb = outlen - mul;
 
         if (vlc_iconv (hd, &inp, &inb, &outp, &outb) != (size_t)(-1))
         {
             *outsize = outlen - outb;
+            outb += mul;
             inb = 1; /* append nul terminator if possible */
             if (vlc_iconv (hd, &inp, &inb, &outp, &outb) != (size_t)(-1))
                 break;