Add ps -Z.

As with ls, it doesn't seem like -Z should be guarded behind LSM
availability. On a non-SELinux system, the label is always "unconfined".
diff --git a/lib/lib.c b/lib/lib.c
index d9bea89..aa7b1c3 100644
--- a/lib/lib.c
+++ b/lib/lib.c
@@ -342,6 +342,14 @@
   return try;
 }
 
+char *chomp(char *s)
+{
+  char *p = strrchr(s, '\n');
+
+  if (p) *p = 0;
+  return s;
+}
+
 int unescape(char c)
 {
   char *from = "\\abefnrtv", *to = "\\\a\b\033\f\n\r\t\v";