attach() EINTR with signal handlers

[vbraun]

E.g. resizing a terminal while file is attached crashes with

  File "/mnt/disk/home/release/Sage/local/lib/python2.7/site-packages/sage/repl/inputhook.py", line 34, in sage_inputhook
    r, w, e = select.select([f], [], [], TIMEOUT)
select.error: (4, 'Interrupted system call')

Component: user interface

Issue created by migration from https://trac.sagemath.org/ticket/21712

[vbraun]

comment:1

Duplicate of #21711