Makes a binary diff of two files and stores the result in a patch file.
This function works with both text and binary files. Resulting patch
file can be later applied using xdiff_file_bpatch()/xdiff_string_bpatch().
Parameters
old_file
Path to the first file. This file acts as "old" file.
new_file
Path to the second file. This file acts as "new" file.
dest
Path of the resulting patch file. Resulting file contains differences
between "old" and "new" files. It is in binary format and is human-unreadable.