Syntax file for M4/Autoconf

[Andrew V. Samoilov]

Hi!

I can't hightlight quoted document-here parts in the sh like
cat << 'EOF'
$$$
EOF

Also I want to add case insensitive keywords to the editor syntax 
engine, but I have some ideas how to change syntax file syntax.
Possibly solution are:
1) make contextes case insensitive by adding case-insensitive keyword at 
the end of context line.
2) add new keyword like ikeyword for case-insensitive keywords
3) add case-insensitive clause at the end of each case insensitive keywords

Your suggestions are welcome

--
Regards,
Andrew V. Samoilov.