Depends for what you want. Do you want to install all .m files or only the .m in "${S}".
```
$ spm8.zip
$ find spm8 -maxdepth 1 -name "*.m" | wc -l
590
$ find spm8 -maxdepth 10 -name "*.m" | wc -l
2886
```

bash expands ``"${S}/*.m`` into 590 files, which then get installed. If you want to install all 2886 files, you have to do something more, but what depends on if you want to install them flat in ``$(octave-config --m-site-dir)`` or in the same  sub-directory structure as in ``${S}``