[screen/f19] (4 commits) ...Segfault in alternate screen handling (#948617)

[Petr Hracek]

Summary of changes:

  24411c0... Fix (#907472) xterm too long - sorry. (*)
  6d60390... Related: (#907472) xterm too long - sorry. (*)
  d443bf9... Segfault in alternate screen handling (#948617) (*)
  5d9f6f9... Segfault in alternate screen handling (#948617)

(*) This commit already existed in another branch; no separate mail sent