>> I can't remember how I
>> managed to get nsgmls to work to check impnotes.xml.
>$ cd clisp/doc
>$ make check
I knew this. Doesn't work for me.
And I already used this nsgmls to verify other XML schemata (not docbook).
[5 hours lost in various trials]
Now I have it:
make impnotes.xml DTDVER=4.2 DTD=/usr/share/sgml/db42xml/docbookx.dtd
wrong: make impnotes.xml DTDVER=4.2 DTD=/usr/share/sgml/docbook_4.2/docbookx.dtd
nsgmls -s -wxml -E50 -c /usr/share/doc/packages/sp/html-xml/xml.soc impnotes.xml