Auto-enabling syntax highlighting if we can guess Vim's background color

[Jason A. Spiro]

Thank you very much for your work on Vim.

In certain cases, Vim can quite-reliably guess the background color:

- On rxvt and its derivatives.
(See src/option.c:term_bg_default(), viewable online at
<http://code.google.com/p/vim/source/search?q=^term_bg_default()>.)
- When the GUI is running.

In other cases, it can somewhat-reliably guess the background color:

- On Windows, on the Linux console, on Cygwin, and on PuTTY.
(These all have black backgrounds by default, and I assume the vast
majority of users don't change the background-color settings.)

I wonder if you could please enable Vim's syntax highlighting by default, at
least on platforms where you can reliably guess the background color.

[Ben Fritz]

I think the reason for not having syntax on by default has nothing to do with whether Vim knows the background color, but rather, that some people don't want it turned on, and historically the feature didn't exist. One of the biggest considerations in Vim's development is backwards compatibility and "don't surprise the users".