The `PARSE_ARGV` mode was recently added to help functions properly
parse their arguments even when those arguments may be quoted and
contain literal `;` in their values. Fix the implementation to encode
`;`s in reported multi-value arguments and in `UNPARSED_ARGUMENTS` so
that `;`s in the individual values are preserved in the lists. This
allows clients to access all their argument values correctly.
The `ARGC`/`ARGV#` variables in function scope hold the original
arguments with no ;-list flattening. Add a way for functions to
cleanly parse arguments that may contain `;`. This also avoids
extra copying of the arguments.
Co-Author: Brad King <brad.king@kitware.com>
Matthew Woehlke
Bill Hoffman