Work to get rid of GCC 4.0 warnings, part 1.

Work to get rid of GCC 4.0 warnings, part 1.

In many files, change count parameters to parse_variables(),
etc. from `int' to `size_t'.  Also change related variables and
struct members.  Also change messages as needed (e.g. %d to %u
with cast to unsigned).  Also change arithmetic as necessary
(e.g. n >= m - 1 to n + 1 >= m).