The Nixpkgs documentation on the linux kernel builders focused on
using and extending kernels that were already packaged, but never
mentioned that it's possible to also build a kernel almost "from
scratch".
The NixOS documentation went a bit deeper on manual linux kernel
configs, but that information wasn't particularly NixOS-specific.
This commit consolidates the information related to building the
kernel on Nixpkgs's documentation, while keeping any additional
NixOS-specific information on NixOS's documentation.
An additional README.md was created for contributor-facing
documentation.
https://hydra.nixos.org/build/241116326/nixlog/1
```
build flags: SHELL=/nix/store/x1xxsh1gp6y389hyl40a0i74dkxiprl7-bash-5.2-p15/bin/bash PREFIX=\$\(out\) CC=cc
cc -F/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Frameworks -I/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include -fblocks -c -o CoreSymbolication.o CoreSymbolication.c
In file included from CoreSymbolication.c:1:
./CoreSymbolication.h:393:1: error: type specifier missing, defaults to 'int'; ISO C99 and later do not support implicit int [-Wimplicit-int]
CSSymbolOwnerSetTransientUserData(CSSymbolOwnerRef owner, uint32_t gen);
^
int
1 error generated.
```
Also submitted patch upstream at
https://github.com/matthewbauer/CoreSymbolication/pull/1
ZHF: #265948
stdenv.targetPlatform really shouldn't be used by software that
doesn't generate or manipulate binaries. I reviewed all uses of
targetPlatform outside of pkgs/development/compilers and pkgs/stdenv
and replaced those which weren't involved in something which fits
these criteria.
