Pre-7.3 Vim Colorcolumn-like hack

.vimrc

"  80-character limit highlighting for vim <7.3 Replace colorcolumn commands with
"   the following commands
    " Highlight 78-80 in 'Search' color
    au BufWinEnter * let w:m1=matchadd('Search', '\%<81v.\%>77v', -1)

    " Highlight past column 80 in 'ErrorMsg' color
    au BufWinEnter * let w:m2=matchadd('ErrorMsg', '\%>80v.\+', -1)

    " Highlight only column 81 (when it has characters in it)
    au BufWinEnter * let w:m2=matchadd('ErrorMsg', '\%81v.\+', -1)