more careful treatment of context visibility for rule declarations (see also 39d9c7f175e0, e639d91d9073) -- avoid duplicate warnings;
syntax: glob
*~
*.class
*.jar
*.marks
*.orig
*.rej
.DS_Store
.swp
syntax: regexp
^contrib
^heaps/
^browser_info/
^doc/.*\.dvi
^doc/.*\.eps
^doc/.*\.pdf
^doc/.*\.ps
^src/Tools/jEdit/dist/