Fix a few regression test failures (#222)

src/cmd/ksh93/tests/_common:
- Commit aed5c6d7 renamed the err_exit function,
  breaking a few tests in glob.sh that call the function
  directly instead of using the alias. Restore the function.

src/cmd/ksh93/tests/builtins.sh:
- The dtksh builtins don't have optget option parsing, so
  skip the unrecognized options test for those (this of
  course only has relevance when running dtksh against the
  regression tests).

src/cmd/ksh93/tests/pty.sh:
- If the vi editor couldn't be found on the $PATH, skip the
  regression test that involves it.

src/cmd/ksh93/tests/_common

@@ -19,7 +19,12 @@ _message()
 {
 	print -r $'\t'"${Command}[$1]: ${@:2}" >&2
 }
-alias err_exit='_message "$((Errors++,LINENO))"'   # inaccurate err_exit name kept for historical integrity :)
+function err_exit
+{
+	_message "$@"
+	let Errors+=1
+}
+alias err_exit='err_exit $LINENO'  # inaccurate err_exit name kept for historical integrity :)
 alias warning='_message "$LINENO" "warning:"'
 
 Command=${0##*/}