Description of problem:

If the /usr/share/sgml/xml.dcl file is used for validation, ie:

  nsgmls -s -v /usr/share/sgml/xml.dcl myfile.xml

it will silently ignore some mistakes, because the .dcl file has IMPLYDEF 
set to YES for everything. For example if you add an attribute to an element 
that isn't supposed to have any, it won't report it.

I got the expected results with /usr/share/doc/openjade-1.3/xml.dcl from 
openjade-1.3-6. I don't know which is the "best" or official version but I 
believe the one included with openjade should be used.


Steps to Reproduce:

nsgmls -v -s /usr/share/sgml/xml.dcl test.xml

test.xml is the following:
-------------------------------------------------------------
<?xml version="1.0"?>
<!DOCTYPE test [
  <!ELEMENT test EMPTY>
  <!ATTLIST test cat CDATA #IMPLIED>
]>
<test dog="spot"/>
------------------------------------------------------------------


Actual Results:
nsgmls:I: OpenSP version "1.3.4"



Expected Results:
nsgmls:I: OpenSP version "1.3.4"
nsgmls:test.xml:6:10:E: there is no attribute "dog"