xdp socket support (AF_XDP) is the new way of implementing high
performance networking on linux. on arch linux and debian this is
already enabled (checked via the links from the nixos manual).

moreover, these flags are suggested by the bpf documentation at cilium:

https://cilium.readthedocs.io/en/latest/bpf/#compiling-the-kernel

additionally the flag `BPF_JIT_ALWAYS_ON` on was suggested to help
spectre attack mitigations:

torvalds/linux@290af86

So users don’t need to override the $out/etc/security files, we need
to manually set this to /etc. Override it in the install phase so that
we still get the example $out/etc/security files .

Fixes #76713

(cherry picked from commit 716b064)

Don't set `src` in override (?!), or name.

linux-pam: set sconfigdir to /etc for usage at runtime

systemd: fix version after update to 243.4 (#76134)

xorg.libXpm: 3.5.12 -> 3.5.13

libedit: 20191025 -> 20191231

firejail: 0.9.60 -> 0.9.62

flyway: 6.1.2 -> 6.1.3

Tested nixos.tests.installed-tests.gdk-pixbuf.x86_64-linux
atop the current nixpkgs master.

hdf5: 1.10.5 -> 1.10.6

fldigi: 4.1.08 -> 4.1.08.51

- This commit adjust the tests to the ones that are found in the
  tox.ini file for the specified version of the module
- This means we'll have 3 tests in adition to the default one

Building libselinux 2.9 with python 3.8 causes several linker failures[1].
As this breaks several packages on staging and the glibc-230 integration
jobset[2], this should be fine as workaround.

This change can be reverted when updating to libselinux 3.0, ArchLinux
already has `libselinux` 3.0 with python 3.8[3].

[1] https://hydra.nixos.org/build/109960000
[2] https://hydra.nixos.org/eval/1564244
[3] https://aur.archlinux.org/cgit/aur.git/commit/?h=libselinux&id=f717bef8131622ad8545f4bdffe7bafdc35e9808

Fixes #77266: CVE-2019-1551
https://www.openssl.org/news/secadv/20191206.txt

This enables to compile rls and rustc

See also rust-lang/rust#64823

gtk3: fix missing header file on darwin

This was only introduced in 1.40.0 and doesn't work on older versions.

    thread 'main' panicked at 'Error: no rules matched rustc-dev.', src/bootstrap/builder.rs:231:21
    note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
    failed to run: /build/rustc-1.38.0-src/build/bootstrap/debug/bootstrap dist rustc-dev

rustPackages: make rustc-dev optional