Update SystemRescueCd to 6.0.0+

[nl6720]

SystemRescueCd is now based on Arch Linux.

[asmodehn]

I tested this PR and it booted fine for me (sysrescd 603)

[sebma]

@nl6720 In your 34dd8c6 commit, you should first archive inc-sysrescd.cfg into something like inc-sysrescd5.cfg add a menuentry "SystemRescueCd <= 5 >" for it in grub.cfg to also keep the ability to boot on SystemRescueCD v5 for those can't stand using systemd because of some of systemd bugs.

Moreoever, in your same commit, so as to differentiate SystemRescueCd v<=5 from SystemRescueCd >=6, can you please replace in inc-sysrescd.cfg and in grub.cfg :

for isofile in ${isopath}/sysrescd/systemrescuecd-*.iso; do by : for isofile in ${isopath}/sysrescd/systemrescuecd-amd64-*.iso ${isopath}/sysrescd/systemrescuecd-i686-*.iso; do

and in sysrescd5.cfg replace :

for isofile in ${isopath}/sysrescd/systemrescuecd-*.iso; do by : for isofile in ${isopath}/sysrescd/systemrescuecd-x86-*.iso; do

[sebma]

@nl6720 BTW : I've just discovered that Thias had already added support for SystemRescueCD v6 in his glim2 branch which has quite a lot of updates which you can compare with the master branch here.