sys-libs/glibc: drop devpts mount checks, bug #704780

sys-libs/glibc: drop devpts mount checks, bug #704780

USE=-suid is a defaut for a while. The check made sense
when transition from USE=suid -> USE=-suid was happening.

Should not be needed nowadays.

The check fails in private-users containers where devpts
is mounted as a private group:

  # systemd-nspawn --private-users=65536 -D amd64-stable-glibc-2.30
  Selected user namespace base 65536 and range 65536
  amd64-stable-glibc-2.30 # fgrep pts /proc/mounts
  devpts /dev/pts devpts
    rw,nosuid,noexec,relatime,gid=65541,mode=620,ptmxmode=666 0 0

PTYs still work in that setup. I guess due to ptmxmode=666
broad permissions. Let's drop the old check and allow more
pts configurations.

Reported-by: Kai Krakow
Closes: https://bugs.gentoo.org/704780
Package-Manager: Portage-2.3.96, Repoman-2.3.22
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>