Ubuntu patch prevents custom argv[0]

[Etienne]

On Ubuntu 24.04.03 starting e.g. `true` with a custom argv[0] works:

```
ecordonnier@LBM9V6C4:~/dev/coreutils$ bash -c "exec -a foobar
/usr/lib/cargo/bin/coreutils/true"
foobar 0.0.24 (multi-call binary)

Usage: foobar [function [arguments...]]

Currently defined functions:

    [, arch, b2sum, b3sum, base32, base64, basename, basenc, cat,
chcon, chgrp, chmod, chown,
    chroot, cksum, comm, cp, csplit, cut, date, dd, df, dir,
dircolors, dirname, du, echo,
...
...
```

On Ubuntu 26.04 (development branch) it doesn't work:
```
asteba@asteba-MS-7C75:~$ /usr/lib/cargo/bin/coreutils/true --version
/usr/lib/cargo/bin/coreutils/true (uutils coreutils) 0.2.2

asteba@asteba-MS-7C75:~$ bash -c "exec -a foobar /usr/lib/cargo/bin/coreutils/true"
Security violation: Requested utility `foobar` does not match executable name:
  /usr/lib/cargo/bin/coreutils/true
```

It works with GNU coreutils however:

```
asteba@asteba-MS-7C75:~/dev$ bash -c "exec -a foobar /usr/bin/gnutrue"
asteba@asteba-MS-7C75:~/dev$
```

The error "Security Violation..." comes from a Ubuntu patch ( https://git.launchpad.net/ubuntu/+source/rust-coreutils/tree/debian/patches/require-utility-to-be-invoked-at-matching-path.patch?h=applied/ubuntu/devel ):

```
asteba@asteba-MS-7C75:~/dev/coreutils/ubuntu-sources$ rg -i "security violation" .
./rust-coreutils-0.2.2/debian/patches/require-utility-to-be-invoked-at-matching-path.patch
27:+ "Security violation: Requested utility `{}` does not match executable name:\n {}",

./rust-coreutils-0.2.2/src/bin/coreutils.rs
116: "Security violation: Requested utility `{}` does not match executable name:\n {}",

```

@julian-klode FYI

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Julian Andres Klode (juliank)]

Yes this is necessary for security reasons, there is not much we can do except restructure coreutils entirely to be build as a shared library with tiny stub executables call uu_main()