A shallow git checkout leads to version number generation that is invalid and makes a build fail:

```
git clone --single-branch --depth 1 --shallow-submodules --branch gtk2 git://git.claws-mail.org/claws.git claws-mail
./autogen.sh
make
```

fails with errors like

```
claws.c: In function 'claws_get_version':
version.h:32:54: error: invalid suffix "d76d2" on integer constant
   32 | #define VERSION_NUMERIC         MAKE_NUMERIC_VERSION(5d76d2, 5d76d2, \
      |                                                      ^~~~~~
```

After the `./autogen`, there is a file `version` which contains  
```
echo 5d76d2
```

If instead of the above git clone command I use

```
git clone git://git.claws-mail.org/claws.git claws-mail
git switch gtk2
git checkout gtk2
./autogen.sh
make
```

those errors does not occur, and `version` contains  
```
echo 3.19.0-48-g5d76d2
```

Regards!