dash: built-in variable LINENO mandated by POSIX not there

[Rocky Bernstein]

Package: dash
Version: 0.5.4-8ubuntu1
Severity: normal

In Section 2.5.3, Shell Variables [XCU 2303] LINENO seems to be mandated:

Set by the shell to a decimal number representing the current
sequential line number (numbered starting with 1) within a script or
function before it executes each command. If the user unsets or resets
LINENO, the variable may lose its special meaning for the life of the
shell. If the shell is not currently executing a script or function,
the value of LINENO is unspecified. This  volume of POSIX.1-200x
specifies the effects of the variable only for systems supporting the
User Portability Utilities option.

If desired, I can work up a patch. Harder however is to get the line
number to give more accurate results and this might be considered a
separate bug since in accurate line numbers appear in general errors
reported by dash.

-- System Information:
Debian Release: lenny/sid
  APT prefers hardy-updates
  APT policy: (500, 'hardy-updates'), (500, 'hardy-security'), (500, 'hardy')
Architecture: i386 (i686)

Kernel: Linux 2.6.24-16-generic (SMP w/1 CPU core)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages dash depends on:
ii  debianutils              2.28.2-0ubuntu1 Miscellaneous utilities specific t
ii  libc6                    2.7-10ubuntu3   GNU C Library: Shared libraries

dash recommends no packages.

-- debconf information:
  dash/sh: true