Sometimes mailers, editors, or other programs change spaces into tabs,
or vice versa. If this happens to a patch file or an input file, the
files might look the same, but patch will not be able to match
them properly. If this problem occurs, use the `-l' or
`--ignore-white-space' option, which makes patch compare
white space loosely so that any sequence of white space in the patch file
matches any sequence of white space in the input files. Non-white-space
characters must still match exactly. Each line of the context must
still match a line in the input file.