uboot: (firmwareOdroidC2/C4) don't invoke patch tool, use patches = [] instead

https://github.com/NixOS/nixpkgs/blob/master/pkgs/stdenv/generic/setup.sh#L948
this can do it nicely.

Signed-off-by: Anton Arapov <anton@deadbeef.mx>

doc/builders/images/appimagetools.section.md

@@ -0,0 +1,48 @@
+# pkgs.appimageTools {#sec-pkgs-appimageTools}
+
+`pkgs.appimageTools` is a set of functions for extracting and wrapping [AppImage](https://appimage.org/) files. They are meant to be used if traditional packaging from source is infeasible, or it would take too long. To quickly run an AppImage file, `pkgs.appimage-run` can be used as well.
+
+::: {.warning}
+The `appimageTools` API is unstable and may be subject to backwards-incompatible changes in the future.
+:::
+
+## AppImage formats {#ssec-pkgs-appimageTools-formats}
+
+There are different formats for AppImages, see [the specification](https://github.com/AppImage/AppImageSpec/blob/74ad9ca2f94bf864a4a0dac1f369dd4f00bd1c28/draft.md#image-format) for details.
+
+- Type 1 images are ISO 9660 files that are also ELF executables.
+- Type 2 images are ELF executables with an appended filesystem.
+
+They can be told apart with `file -k`:
+
+```ShellSession
+$ file -k type1.AppImage
+type1.AppImage: ELF 64-bit LSB executable, x86-64, version 1 (SYSV) ISO 9660 CD-ROM filesystem data 'AppImage' (Lepton 3.x), scale 0-0,
+spot sensor temperature 0.000000, unit celsius, color scheme 0, calibration: offset 0.000000, slope 0.000000, dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.18, BuildID[sha1]=d629f6099d2344ad82818172add1d38c5e11bc6d, stripped\012- data
+
+$ file -k type2.AppImage
+type2.AppImage: ELF 64-bit LSB executable, x86-64, version 1 (SYSV) (Lepton 3.x), scale 232-60668, spot sensor temperature -4.187500, color scheme 15, show scale bar, calibration: offset -0.000000, slope 0.000000 (Lepton 2.x), scale 4111-45000, spot sensor temperature 412442.250000, color scheme 3, minimum point enabled, calibration: offset -75402534979642766821519867692934234112.000000, slope 5815371847733706829839455140374904832.000000, dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.18, BuildID[sha1]=79dcc4e55a61c293c5e19edbd8d65b202842579f, stripped\012- data
+```
+
+Note how the type 1 AppImage is described as an `ISO 9660 CD-ROM filesystem`, and the type 2 AppImage is not.
+
+## Wrapping {#ssec-pkgs-appimageTools-wrapping}
+
+Depending on the type of AppImage you're wrapping, you'll have to use `wrapType1` or `wrapType2`.
+
+```nix
+appimageTools.wrapType2 { # or wrapType1
+  name = "patchwork";
+  src = fetchurl {
+    url = "https://github.com/ssbc/patchwork/releases/download/v3.11.4/Patchwork-3.11.4-linux-x86_64.AppImage";
+    sha256 = "1blsprpkvm0ws9b96gb36f0rbf8f5jgmw4x6dsb1kswr4ysf591s";
+  };
+  extraPkgs = pkgs: with pkgs; [ ];
+}
+```
+
+- `name` specifies the name of the resulting image.
+- `src` specifies the AppImage file to extract.
+- `extraPkgs` allows you to pass a function to include additional packages inside the FHS environment your AppImage is going to run in. There are a few ways to learn which dependencies an application needs:
+  - Looking through the extracted AppImage files, reading its scripts and running `patchelf` and `ldd` on its executables. This can also be done in `appimage-run`, by setting `APPIMAGE_DEBUG_EXEC=bash`.
+  - Running `strace -vfefile` on the wrapped executable, looking for libraries that can't be found.