- combine_diff() took cnt (count) which is unsigned in nature but the
parameter type was declared as "int";
- find_next() took "uninteresting" parameter, which masked a static
function of the same name;
- show_parent_lno() took an unused parameter "cnt";
- show_patch_diff() used a local variable in nested inner scope with
the same name with different type, masking the one in the outer scope;
- the last loop in show_patch_diff iterated over lines so it should use
the local variable "lno"