Remove compat code for XEmacs and pre-Emacs 20 Emacs in pcomplete.el

* lisp/pcomplete.el (pcomplete-event-matches-key-specifier-p)
(pcomplete-read-event, pcomplete-show-completions): Remove XEmacs
support and mark now-trivial defaliases as obsolete.
1 job for master in 2 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
failed #2129
test-all

00:00:02

 
Name Stage Failure
failed
test-all Test There has been a runner system failure, please try again
Running with gitlab-runner 11.6.0 (f100a208)
on gitlab-runner-docker cff9d373
Using Docker executor with image debian:stretch ...
Pulling docker image debian:stretch ...
Using docker image sha256:e1de74e67cc70422153600785c4ce4c29843a0e59e18b634c52ca133c564437f for debian:stretch ...
ERROR: Job failed (system failure): Error response from daemon: failed to start shim: exec: "docker-containerd-shim": executable file not found in $PATH: unknown (executor_docker.go:1018:0s)