Comment 2 for bug 919899

On precise I'm getting ç in both firefox and emacs using both compose+apostrophe+c and compose+comma+c.

According to this page, the latter is correct, the former should make c-acute.
http://www.hermit.org/Linux/ComposeKeys.html

However I don't think xkeyboard-config is controlling the compose keys. I think I may have found the source of the error in /etc/console-setup/compose.ISO-8859-1.inc:

compose '´' 'A' to 'Á'
compose '´' 'C' to 'Ç'
compose '´' 'E' to 'É'
compose '´' 'I' to 'Í'
compose '´' 'O' to 'Ó'
compose '´' 'U' to 'Ú'
compose '´' 'Y' to 'Ý'
compose '´' '\'' to '´'
compose '´' 'a' to 'á'
compose '´' 'c' to 'ç'
compose '´' 'e' to 'é'
compose '´' 'i' to 'í'
compose '´' 'o' to 'ó'
compose '´' 'u' to 'ú'
compose '´' 'y' to 'ý'

And in console-setup/Keyboard/locale/iso8859-1:
...
<Multi_key> <acute> <C> : "\307" Ccedilla
<Multi_key> <acute> <c> : "\347" ccedilla
<Multi_key> <C> <comma> : "\307" Ccedilla
<Multi_key> <comma> <C> : "\307" Ccedilla
<Multi_key> <c> <comma> : "\347" ccedilla
<Multi_key> <comma> <c> : "\347" ccedilla
...
<dead_cedilla> <C> : "\307" Ccedilla
<dead_cedilla> <c> : "\347" ccedilla
...
# Useful for portuguese language
<dead_acute> <C> : "\307" Ccedilla
<dead_acute> <c> : "\347" ccedilla