Since 2.44_01, the behaviour for `check_lib` in their `Makefile.PL` has
been "fixed" to fail when the `assert_lib` function fails to build the
test.

 * cpan-authors/XML-Parser@2bc1e90

Now, this wouldn't be so bad, since it's good to actually test what
stuff is being compiled against.

Except that *something* is wonky with the cross-compilation build-time
Perl.

```
Undefined subroutine &File::Temp::mktemp called at inc/Devel/CheckLib.pm line 236.
```

As far as I know, this is a built-in function from Perl.

 * https://perldoc.perl.org/File/Temp.html

Though, something *else* is wrong with `Checklib.pm`. Side-stepping the
issue by (eww) shelling out to `mktemp`, we get these errors:

```

/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-armv7l-unknown-linux-gnueabihf-binutils-2.31.1/bin/armv7l-unknown-linux-gnueabihf-ld: assertlib_src1_0.553056903257133: file not recognized: file truncated
collect2: error: ld returned 1 exit status
 -I/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-expat-2.2.8-armv7l-unknown-linux-gnueabihf-dev/include -L/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-expat-2.2.8-armv7l-unknown-linux-gnueabihf/lib -lexpat
/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-armv7l-unknown-linux-gnueabihf-binutils-2.31.1/bin/armv7l-unknown-linux-gnueabihf-ld: assertlib_src2_0.262169388446154: file not recognized: file truncated
collect2: error: ld returned 1 exit status
Can't link/include C library 'expat.h', 'expat', aborting.
```

Meanwhile, the actual build, while building the library, seemingly has
no issues building using those paths. `¯\_(ツ)_/¯`

This will switch the default TCP congestion control algorithm from
new Reno to CUBIC. CUBIC is the default since Linux kernel 2.6.19
(see 597811ec167fa) and most (all?) distributions keep this default
(e.g. Debian and Ubuntu). On NixOS the default was still new Reno
because generate-config.pl changes TCP_CONG_CUBIC from y to m (since we
try to build everything as a module by default).

To check the active and available algorithms:
$ sysctl net.ipv4.tcp_congestion_control
net.ipv4.tcp_congestion_control = cubic
$ sysctl net.ipv4.tcp_available_congestion_control
net.ipv4.tcp_available_congestion_control = cubic reno

Note: E.g. x86_64_defconfig sets TCP_CONG_CUBIC=y indirectly via
CONFIG_TCP_CONG_ADVANCED=y (but CUBIC is also the default if set to no,
see net/ipv4/Kconfig).

These are expected to be here for Windows compilation. The change in
e1831eb didn’t move these
correctly (while still patching the search paths).

https://hydra.nixos.org/build/114202790

It appears that cairo's configure script, at least on MacOS but perhaps
elsewhere, unconditionally enables xlib support, even if the library
isn't present, which breaks the build on MacOS always (since x11 is
disabled by default now). This explicitly passes `--disable-x11` if
x11Support is set to false, which fixes the build for me.

"Not a lot of changes in this release, most are related to fixing output
formatting and documentation." [0]

File changes (additions/removals):
+share/man/man8/tc-ets.8.gz
+share/man/man8/tc-fq_pie.8.gz

nix path-info -S:
5.5.0 51509616
5.6.0 51528680

[0]: https://marc.info/?l=linux-netdev&m=158585608413591

- Need custom pkg-config setting
- add wayland & libxkbcommon

They will be installed now and we can provide $HOSTCC for
cross-compilation.

New files:
+lib/tc/experimental.dist
+lib/tc/normal.dist
+lib/tc/pareto.dist
+lib/tc/paretonormal.dist

Note: The distributions are generated in a reproducible way.

Co-Authored-By: Benjamin Saunders <ben.e.saunders@gmail.com>

linux config: Set TCP_CONG_CUBIC=yes to restore the default

gsm: 1.0.18 -> 1.0.19

- add glib to nativeBuildInputs
- only update loaders cache on native builds

This is needed in cross where systemd is not in path.

Also set wayland-scanner to proper path

These should be runtime, not build time deps

Unfortunately, we need to emulate the system to get a real cache.
Native version doesn’t know the right paths.

We can’t cross-compile the cache, so just skip it for now.

This prevents duplication in cross-compiled nixos machines. The
bootstrapped glibc differs from the natively compiled one, so we get
two glibc’s in the closure. To reduce closure size, just use
stdenv.cc.libc where available.

- adds utilmacros
- set null malloc flag

- Needs to be like <cpu>-<os>-gcc.
- Remove unneeded --enable-external-build flag
    This confuses the feature detection and is not needed for cross
    compilation anymore.

Can’t run these on cross anyway