cdrtools: smake optional_depends.
cdrkit: Conflicts with dirsplit
dirsplit: Conflicts with cdrkit
cdrtools: Configure cdrkit compatibility
cdrkit: Configure cdrtools compatibility
dvdrtools: Configure cdrkit compatibility
Aliases added for cdrecord and alike tools

alias includes, but not limited to:
- cdrecord
- mkisofs
- cdda2wav
Merge remote-tracking branch 'cavalier/cdrecord'

aliases
VirtualBox: depend on CDR alias