terminal-unix: reject overlong termcap strings

Our own tables have size for only 8 chars, so these sequences must be
rejected. It seems strings of length 8 are still ok, because the code
uses memcmp and not strcmp, so still allow these.

Based on mplayer-svn commit r37129.

osdep/terminal-unix.c

@@ -87,6 +87,9 @@ static char *term_smkx = NULL;
 #endif
 
 static keycode_st *keys_push(char *p, int code) {
+    if (strlen(p) > 8)
+        return NULL;
+
     if (getch2_keys.len == getch2_keys.cap) {
         getch2_keys.cap *= 2;
         if (getch2_keys.cap == 0)