treewide: replace `stdenv.is` with `stdenv.hostPlatform.is`

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"
```

3 files changed, 7 insertions, 7 deletions

diff --git a/pkgs/development/perl-modules/ImageExifTool/default.nix b/pkgs/development/perl-modules/ImageExifTool/default.nix
index 08d207e3bbac..46efb33f23ca 100644
--- a/pkgs/development/perl-modules/ImageExifTool/default.nix
+++ b/pkgs/development/perl-modules/ImageExifTool/default.nix
@@ -18,9 +18,9 @@ buildPerlPackage rec {
     hash = "sha256-sfSnx5bS7vI0KIhBOpB5VYzP6g8oi0rR7mUTxxNWEA0=";
   };
 
-  nativeBuildInputs = lib.optional stdenv.isDarwin shortenPerlShebang;
+  nativeBuildInputs = lib.optional stdenv.hostPlatform.isDarwin shortenPerlShebang;
 
-  postInstall = lib.optionalString stdenv.isDarwin ''
+  postInstall = lib.optionalString stdenv.hostPlatform.isDarwin ''
     shortenPerlShebang $out/bin/exiftool
   '';
 
diff --git a/pkgs/development/perl-modules/WWW-YoutubeViewer/default.nix b/pkgs/development/perl-modules/WWW-YoutubeViewer/default.nix
index cba9ef986362..0669f5b7c7af 100644
--- a/pkgs/development/perl-modules/WWW-YoutubeViewer/default.nix
+++ b/pkgs/development/perl-modules/WWW-YoutubeViewer/default.nix
@@ -22,14 +22,14 @@ buildPerlPackage rec {
     sha256 = "9Z4fv2B0AnwtYsp7h9phnRMmHtBOMObIJvK8DmKQRxs=";
   };
 
-  nativeBuildInputs = lib.optional stdenv.isDarwin shortenPerlShebang;
+  nativeBuildInputs = lib.optional stdenv.hostPlatform.isDarwin shortenPerlShebang;
   propagatedBuildInputs = [
     LWP
     LWPProtocolHttps
     DataDump
     JSON
   ];
-  postInstall = lib.optionalString stdenv.isDarwin ''
+  postInstall = lib.optionalString stdenv.hostPlatform.isDarwin ''
     shortenPerlShebang $out/bin/youtube-viewer
   '';
 
diff --git a/pkgs/development/perl-modules/strip-nondeterminism/default.nix b/pkgs/development/perl-modules/strip-nondeterminism/default.nix
index e50d61b87898..fe6328ea3946 100644
--- a/pkgs/development/perl-modules/strip-nondeterminism/default.nix
+++ b/pkgs/development/perl-modules/strip-nondeterminism/default.nix
@@ -24,7 +24,7 @@ buildPerlPackage rec {
   };
 
   strictDeps = true;
-  nativeBuildInputs = lib.optionals stdenv.isDarwin [ shortenPerlShebang ];
+  nativeBuildInputs = lib.optionals stdenv.hostPlatform.isDarwin [ shortenPerlShebang ];
   buildInputs = [
     ArchiveZip
     ArchiveCpio
@@ -45,7 +45,7 @@ buildPerlPackage rec {
     # we don’t need the debhelper script
     rm $out/bin/dh_strip_nondeterminism
     rm $out/share/man/man1/dh_strip_nondeterminism.1
-  '' + lib.optionalString stdenv.isDarwin ''
+  '' + lib.optionalString stdenv.hostPlatform.isDarwin ''
     shortenPerlShebang $out/bin/strip-nondeterminism
   '';
 
@@ -56,7 +56,7 @@ buildPerlPackage rec {
   '';
 
   # running shortenPerlShebang in postBuild results in non-functioning binary 'exec format error'
-  doCheck = !stdenv.isDarwin;
+  doCheck = !stdenv.hostPlatform.isDarwin;
   doInstallCheck = true;
 
   meta = with lib; {