Update conf-xkbcommon

[ddeclerck]

Summary of changes :

• use os-family instead of os-distribution to capture more derivatives
• Windows: add the Cygwin package
• Debian & Ubuntu: add os-family = "ubuntu" because some (many ?) Ubuntu derivatives (Linux Mint, elementaryOS, ...) only list Ubuntu in os-release:ID_LIKE (or list both, but Ubuntu first)
• Mandriva and derivatives: add the package for this family
• SUSE/OpenSUSE/SLES: add os-family = "sles" and os-family = "opensuse" to account for the fact that the os-release:ID and os-release:ID_LIKE field usage seems inconsistent across SUSE variants (sometimes "suse", sometimes "sles", sometimes no ID_LIKE field)
• Fedora/RHEL/CentOS: regroup in the same specification (they often share the same package names)
• Arch Linux: add os-family = "archlinux" in addition of os-family = "arch" (I have seen both in Arch and its derivatives)
• Gentoo and derivatives: add the package for this family
• *BSD: use os-family = "bsd" (all BSD variants seem to use the same name for this package)
• MacOS: add the MacPorts package