Bug 2478240

On Fedora 44, invoking 7-Zip as `/bin/7z` fails to load the external
codec/plugin library and reports unsupported archive formats. Invoking
the same installed binary as `/usr/bin/7z` works.

This breaks build systems that discover or cache `7z` as `/bin/7z`
and later use that path to create ZIP archives.

Package version:

```text
7zip-25.01-5.fc44
```

Reproducible: Always

Steps to Reproduce:
1. On a Fedora 44 system where `/bin` is a symlink to `/usr/bin`,
   install `7zip-25.01-5.fc44`.
2. Run:

   ```bash
   /bin/7z i
   ```

3. Try to create a ZIP archive through `/bin/7z`:

   ```bash
   /bin/7z a -tzip /tmp/7zip-test.zip README.md
   ```

4. Compare with the `/usr/bin/7z` invocation:

   ```bash
   /usr/bin/7z i
   ```
Actual Results:
`/bin/7z i` fails to load the codec library:

```text
Codec Load Error: /bin/7z.so
```

ZIP creation through `/bin/7z` fails:

```text
ERROR:
Unsupported archive type
```

The same installed binary works when invoked as `/usr/bin/7z`.

Expected Results:
`/bin/7z` and `/usr/bin/7z` should behave identically when `/bin` is a
symlink to `/usr/bin` and both paths refer to the same executable.

Both invocations should load:

```text
/usr/libexec/7zip/7z.so
```

ZIP archive creation through `/bin/7z` should work.

Additional Information:
The installed filesystem has Fedora's merged-/usr layout:

```text
/bin -> usr/bin
```

`/bin/7z` and `/usr/bin/7z` resolve to the same file:

```text
6469925 /bin/7z
6469925 /usr/bin/7z
```

They also have the same ELF build ID:

```text
BuildID[sha1]=8da5e54ad58094c35a07916c81e1ec63d7182782
```

The difference follows `argv[0]`, not the executed inode:

```bash
bash -c 'exec -a /bin/7z /usr/bin/7z i'
bash -c 'exec -a /usr/bin/7z /bin/7z i'
```

Observed behavior:

- `argv[0]=/bin/7z` fails, even when executing `/usr/bin/7z`.
- `argv[0]=/usr/bin/7z` succeeds, even when executing `/bin/7z`.

Fedora's package carries `7zip-find-so-in-libexec.diff`, which
redirects the external plugin lookup to:

```text
/usr/libexec/7zip/7z.so
```

That downstream patch appears to handle the normal installed path under
`/usr/bin`, but not the merged-/usr alias under `/bin`.

Because 7-Zip derives its module directory from the literal executable
prefix before canonicalizing the path, invoking the binary as `/bin/7z`
bypasses Fedora's libexec redirection and causes 7-Zip to search for:

```text
/bin/7z.so
```

instead of:

```text
/usr/libexec/7zip/7z.so
```

Possible fixes:

- Treat `/bin/` the same as Fedora's installed binary directory under
  `/usr/bin/` in `7zip-find-so-in-libexec.diff`.