Okay, I can confirm the unresolvable gtkdialog repo error (on WD_Void32 version 2.6). My suspicion is that Void repo no longer supporting gtkdialog or only as gtk+3 version and some issue regarding libvte with that (I think that so.9 libvte is for gtk+2 but my memory is hazy on this). You may end up needing to remove that gtkdialog altogether and rely on a gtk+2 version in an sfs (probably including libvte) - in other words, the same gtkdialog I provide in an sfs for WDL_Arch except you'll need a 32bit version of that for WDL_Void32 (and the 64bit version for WDL_Void64).
I'll test now if xbps will remove gtkdialog and work thereafter. Unfortunatly, I haven't really used xbps for a long time so forget the commands... but now reading: https://docs.voidlinux.org/xbps/index.html
So now done:
xbps-remove gtkdialog
and xbps-install -Suy
now seems to be working.
After that, I'll try to put gtkdialog back in with: xbps-install gtkdialog
to see if it is still there... Else try the 10gtkdialog64_libvte.sfs from WDL_Arch64 at boot time for the WDL_Void64 (but as I said you'd need a 32bit version of gtkdialog...sfs for WDL_Void32).
Let's face it, gtkdialog is a dead/pretty-much-unsupported package (and named terribly since same as name of actual gtk+ component) so bigger distros dropping its use altogether. Developers should work towards redrafting their utilities to use something likely to be supported by the upstream repos.