New comment by leahneukirchen on void-packages repository

https://github.com/void-linux/void-packages/pull/32822#issuecomment-963652638

Comment:
For Singular, this is good enough to cross-build:

```
configure_args="--with-readline=ncurses
        --enable-gfanlib
        --enable-Singular
        --enable-factory
        --disable-doc
        --disable-polymake
        --without-python
        --with-libparse
        ac_cv_lib_cddgmp_dd_free_global_constants=yes
        "
```

For cddlib, please add cddlib-devel and also move the binaries that are not relevant for end-users there (or remove them completely).