diff subshell redirection fails

[Jose Mari Mor Fabregat]

Hi,

Trying to use redirection subshell with busybox diff, I've found that
don't run in diff but with others. For testing purposes, I'm trying
this:

$ wget http://www.busybox.net/downloads/busybox-1.20.2.tar.bz2
$ tar ...
$ make menuconfig
  HOSTCC  scripts/basic/fixdep
  HOSTCC  scripts/basic/split-include
  HOSTCC  scripts/basic/docproc
  (...)
  *** End of configuration.
  *** Execute 'make' to build the project or try 'make help'.
$ make
  SPLIT   include/autoconf.h -> include/config/*
  GEN     include/bbconfigopts
  (...)
  Final link with: m
  DOC     busybox.pod
  DOC     BusyBox.txt
  DOC     busybox.1
  DOC     BusyBox.html
$ ./busybox diff <(ls /var) <(ls -1 /var)
$ ./busybox comm <(ls /var) <(ls -1 /var)
                account
                cache
                crash
                cvs
                db
                empty
                games
    (...)
$

I've tested this with different kernels but previous lines in
2.6.32-279.11.1.el6.centos.plus.x686

Thanks for your attention.