[luatex] os.execute

[Dirk Laurie]

In Lua 5.2, the definition of os.execute changed to:

This function is equivalent to the ISO C function system. It passes
command to be executed by an operating system shell. Its first result
is true if the command terminated successfully, or nil otherwise.
After this first result the function returns a string and a number, as
follows:

"exit": the command terminated normally; the following number is the
exit status of the command.
"signal": the command was terminated by a signal; the following number
is the signal that terminated the command.

When called without a command, os.execute returns a boolean that is
true if a shell is available.

In Lua 5.1, it was:

This function is equivalent to the C function system. It passes
command to be executed by an operating system shell. It returns a
status code, which is system-dependent. If command is absent, then it
returns nonzero if a shell is available and zero otherwise.

In LuaTeX, Version beta-0.76.0-2013121407  (TeX Live 2013/dev/Debian),
_VERSION is "Lua 5.2" but os.execute still behaves as in Lua 5.1.

Is this still true in Version 0.85.0? If so, is it a policy decision
that one can rely on?