We're feeding a list of files from `lsdiff` to `filterdiff` via `xargs`.
That list is newline separated, and looks something like this:
```
$ lsdiff <(curl -s 1e86a219f5.patch)
a/README.md
b/files/The Answer to the Ultimate Question of Life, The Universe, and Everything.txt
```
However, if the list contains files with apostrophes in it, xargs freaks
out:
```
$ echo "there's an apostrophe here" | xargs -I{} python -c "import sys; print(sys.argv)" {}
xargs: unmatched single quote; by default quotes are special to xargs unless you use the -0 option
```
The fix is simple, just explicitly specify a delimiter:
```
$ echo "there's an apostrophe here" | xargs -I{} --delimiter='\n' python -c "import sys; print(sys.argv)" {}
['-c', "there's an apostrophe here"]
```
I added 2 tests here:
- `nix-build -A pkgs.tests.fetchpatch.fileWithApostrophe` fails without the code change.
- `nix-build -A pkgs.tests.fetchpatch.fileWithSpace` passes both before
and after this change, but I wanted to add it to prove that I didn't
break anything.
1d32087125