Although this is a release canidate version of kernel 3.12, there are
reasons for merging this anyway, as discussed in #1010 and #1006.
Thanks to @offlinehacker for this and the initial pull request.
This reverts commit 68ce9e91e12914f34e55ef16d8f4b6fbcdd9e92a.
/proc/config.gz is available after "modprobe configs"
and in
/run/booted-system/kernel-modules/config
it helps, but is incomplete.
more fixes are coming, but including these would change too much
generic btrfs code, which might cause trouble for others.
so the best advice is not to use btrfs send yet and wait for 3.11 or 3.12
It has been submitted for inclusion in mainline, so it will probably
make it into 3.11 (or 3.12 as 3.11 is fairly close to release).
It is very local, only affecting people who use the "send" feature.
Without it, send is unstable/unsafe to use incrementally.
It can probably be applied to 3.9 and 3.8 as well, but as I only
tested it against 3.10, so I didn't bother.
It's bad to have the kernel config scattered across two places. (This
should also be done for the other architectures.)
Also, restore Xen and KVM guest support in Linux 3.10.
Having N different copies of the NixOS kernel configuration is bad
because these copies tend to diverge. For instance, our 3.10 config
lacked some modules that were enabled in older configs, probably
because the 3.10 config had been copied off an earlier version of some
older kernel config.
So now there is a single kernel config in common-config.nix. It has a
few conditionals to deal with new/removed kernel options, but
otherwise it's pretty straightforward.
Also, a lot of cut&paste boilerplate between the kernel Nix
expressions is gone (such as preConfigure).
