Background mode detection fails with rxvt-xterm, xterm and konsole

[Hannu Koivisto]

Greetings,

Documentation section General Variables says for TERM: If the value
of `TERM' indicates that Emacs runs in non-windowed mode from
`xterm' or a similar terminal emulator, the background mode
defaults to `light', and Emacs will choose colors that are
appropriate for a light background.

After starting Emacs with -nw -q --no-site-file options in either
rxvt-xterm, xterm or konsole (KDE's terminal emulator), (cdr (assq
'background-mode (frame-parameters))) evaluates to dark, so Emacs
seems to have failed to recognize that it is running in "`xterm' or
a similar terminal emulator".

In xterm and rxvt-xterm TERM is xterm-debian.  In konsole TERM is
xterm.  rxvt-xterm additionally sets COLORTERM (value is
rxvt) and COLORFGBG environment variables.  COLORFGBG's value is
0;15 which seems to indicate the foreground and background
colours in use.

GNU Emacs 21.1 (i686-pc-linux-gnu, X toolkit), running on Debian
GNU/Linux unstable x86, rxvt-xterm 2.6.3), xterm from XFree86
4.1.0 and konsole from KDE 2.2.1.

-- 
Hannu