In preparation for the deprecation of `stdenv.isX`.
These shorthands are not conducive to cross-compilation because they
hide the platforms.
Darwin might get cross-compilation for which the continued usage of `stdenv.isDarwin` will get in the way
One example of why this is bad and especially affects compiler packages
https://www.github.com/NixOS/nixpkgs/pull/343059
There are too many files to go through manually but a treewide should
get users thinking when they see a `hostPlatform.isX` in a place where it
doesn't make sense.
```
fd --type f "\.nix" | xargs sd --fixed-strings "stdenv.is" "stdenv.hostPlatform.is"
fd --type f "\.nix" | xargs sd --fixed-strings "stdenv'.is" "stdenv'.hostPlatform.is"
fd --type f "\.nix" | xargs sd --fixed-strings "clangStdenv.is" "clangStdenv.hostPlatform.is"
fd --type f "\.nix" | xargs sd --fixed-strings "gccStdenv.is" "gccStdenv.hostPlatform.is"
fd --type f "\.nix" | xargs sd --fixed-strings "stdenvNoCC.is" "stdenvNoCC.hostPlatform.is"
fd --type f "\.nix" | xargs sd --fixed-strings "inherit (stdenv) is" "inherit (stdenv.hostPlatform) is"
fd --type f "\.nix" | xargs sd --fixed-strings "buildStdenv.is" "buildStdenv.hostPlatform.is"
fd --type f "\.nix" | xargs sd --fixed-strings "effectiveStdenv.is" "effectiveStdenv.hostPlatform.is"
fd --type f "\.nix" | xargs sd --fixed-strings "originalStdenv.is" "originalStdenv.hostPlatform.is"
```
This was achieved using the following command:
sd 'wrapGAppsHook\b' wrapGAppsHook3 (rg -l 'wrapGAppsHook\b')
And then manually reverted the following changes:
- alias in top-level.nix
- function name in wrap-gapps-hook.sh
- comment in postFixup of at-spi2-core
- comment in gtk4
- comment in preFixup of 1password-gui/linux.nix
- comment in postFixup of qgis/unwrapped-ltr.nix and qgis/unwrapped.nix
- comment in postFixup of telegram-desktop
- comment in postFixup of fwupd
- buildCommand of mongodb-compass
- postFixup of xflux-gui
- comment in a patch in kdePackages.kde-gtk-config and plasma5Packages.kde-gtk-config
- description of programs.sway.wrapperFeatures.gtk NixOS option (manual rebuild)
After making `ffmpeg` point to the latest `ffmpeg_4`, all packages that
used `ffmpeg` without requiring a specific version now use ffmpeg_3
explicitly so they shouldn't change.
