(sgmllib.py): Partial acceptance of patch from David Leonard
<leonard@dstc.edu.au>; allows hyphen and period in the middle
of attribute names. Still not allowed as first character;
as first character these are illegal in the Reference Concrete
Syntax, and we've not identified any use of these characters as
the first char in an attribute name in deployment on the web.
diff --git a/Lib/sgmllib.py b/Lib/sgmllib.py
index 304bbdb..8f32001 100644
--- a/Lib/sgmllib.py
+++ b/Lib/sgmllib.py
@@ -33,7 +33,7 @@
commentclose = regex.compile('--[ \t\n]*>')
tagfind = regex.compile('[a-zA-Z][a-zA-Z0-9]*')
attrfind = regex.compile(
- '[ \t\n]+\([a-zA-Z_][a-zA-Z_0-9]*\)'
+ '[ \t\n]+\([a-zA-Z_][-.a-zA-Z_0-9]*\)'
'\([ \t\n]*=[ \t\n]*'
'\(\'[^\']*\'\|"[^"]*"\|[-a-zA-Z0-9./:+*%?!()_#=~]*\)\)?')