patch 8.0.0096
Problem: When the input or output is not a tty Vim appears to hang.
Solution: Add the --ttyfail argument. Also add the "ttyin" and "ttyout"
features to be able to check in Vim script.
diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt
index b34bf48..1a11a41 100644
--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -8416,6 +8416,8 @@
timers Compiled with |timer_start()| support.
title Compiled with window title support |'title'|.
toolbar Compiled with support for |gui-toolbar|.
+ttyin input is a terminal (tty)
+ttyout output is a terminal (tty)
unix Unix version of Vim.
user_commands User-defined commands.
vertsplit Compiled with vertically split windows |:vsplit|.