ash: fix 'read' shell built-in (2)

Enabling polling in the previous commit resulted in the following
incorrect behaviour:

   { echo -n te; sleep 3; echo st; } | (read -t 1 x; echo "$x")

An empty "$x" is echoed immediately, not after 1 second.

   { echo -n te; sleep 1; echo st; } | (read -t 3 x; echo "$x")

An empty "$x" is echoed immediately.  "test" should be echoed after
1 second.

This arises because poll(2) from gnulib is unable to handle anonymous
pipes properly due do deficiencies in Microsoft Windows.  These have
been acknowledged and fixed in relation to select(2):

   https://lists.gnu.org/archive/html/bug-gnulib/2014-06/msg00051.html

Apply a similar fix to poll(2).

Costs 104-156 bytes.

0 files changed, 0 insertions, 0 deletions