With a C project there is no option to add a new XML file or XML schema file to the project.  It is possible to use a
WEB project to create the file, and then copy it over the the C project, but there is no option to create a new one
within such a project.  Once copied everything seems to work, and you can edit the file and all, you just cannot create
it new.

XML is not just for WEB applications.  It is very useful to exchanging message between two systems as well, which may
have nothing to do with a WEB application.  As much as I do not expect you to ever add the code to parse the file, you
should at least put the option into the list for new files for C projects to create them.