Add NOECHOE and TEST_L to the list of SHOPT options (#242)

src/cmd/ksh93/bltins/print.c:
- Rename the unlisted and misleadingly named SHOPT_ECHOE option
  (which disables, not enables, 'echo -e') to SHOPT_NOECHOE.

src/cmd/ksh93/SHOPT.sh:
- Add the SHOPT_NOECHOE and SHOPT_TEST_L compile time options to
  the list of SHOPT options. Since there is a probe for TEST_L,
  set it to probe (empty) by default. NOECHE is off by default.

src/cmd/ksh93/features/options:
- Small bugfix: Allow SHOPT_TEST_L to be manually enabled on
  systems that don't support '$(whence -p test) -l /foo'.
- Add a comment describing the SHOPT_MULTIBYTE feature test and
  separate it from the SHOPT_DEVFD test.

src/cmd/ksh93/features/options

@@ -28,6 +28,8 @@ tst	note{ SHOPT_* option probe }end cross{
 	# process substitutions instead of FIFOs, which are not as secure
 	ls /dev/fd/9 9<&0 >/dev/null 2>&1
 	option DEVFD $?
+
+	# test for multibyte support
 	case  `echo a | tr a '\012' | wc -l` in
 	*1*)	option MULTIBYTE 0 ;;
 	esac
@@ -40,7 +42,7 @@ tst	note{ SHOPT_* option probe }end cross{
 	# SHOPT_TEST_L so ksh supports it for compatibility with local scripts
 	ln -s /dev/null "$EXECROOT/link$$"
 	env test -l "$EXECROOT/link$$" 2>/dev/null && env test ! -l . 2>/dev/null
-	option TEST_L $?
+	[ $? = 0 ] && option TEST_L 0
 	rm -f "$EXECROOT/link$$"
 
 	# if one of these exists, make SHOPT_SYSRC load /etc/ksh.kshrc by default