memcpy_overlap() replaced with memmove() during the merging.

strings/ctype-tis620.c:
  memcpy_overlap() replaced with memmove() during the merge.

strings/ctype-tis620.c

@@ -498,7 +498,7 @@ static uint thai2sortable(uchar *tstr, uint len)
 	  l2bias use to control position weight of l2char
 	  example (*=l2char) XX*X must come before X*XX
 	*/
-	memcpy_overlap((char*) p, (char*) (p+1), tlen-1);
+	memmove((char*) p, (char*) (p+1), tlen-1);
 	tstr[len-1]= l2bias + t_ctype0[1]- L2_GARAN +1;
 	p--;
 	continue;