zig: reword setup hook

- Move the huge comment from setup-hook.sh to hook.nix
- Prefix zig in the echoCmd calls

pkgs/development/compilers/zig/hook.nix

@@ -9,6 +9,26 @@ makeSetupHook {
   propagatedBuildInputs = [ zig ];
 
   substitutions = {
+    # This zig_default_flags below is meant to avoid CPU feature impurity in
+    # Nixpkgs. However, this flagset is "unstable": it is specifically meant to
+    # be controlled by the upstream development team - being up to that team
+    # exposing or not that flags to the outside (especially the package manager
+    # teams).
+
+    # Because of this hurdle, @andrewrk from Zig Software Foundation proposed
+    # some solutions for this issue. Hopefully they will be implemented in
+    # future releases of Zig. When this happens, this flagset should be
+    # revisited accordingly.
+
+    # Below are some useful links describing the discovery process of this 'bug'
+    # in Nixpkgs:
+
+    # https://github.com/NixOS/nixpkgs/issues/169461
+    # https://github.com/NixOS/nixpkgs/issues/185644
+    # https://github.com/NixOS/nixpkgs/pull/197046
+    # https://github.com/NixOS/nixpkgs/pull/241741#issuecomment-1624227485
+    # https://github.com/ziglang/zig/issues/14281#issuecomment-1624220653
+
     zig_default_flags =
       let
         releaseType =

pkgs/development/compilers/zig/setup-hook.sh

@@ -1,25 +1,5 @@
 # shellcheck shell=bash disable=SC2154,SC2086
 
-# This readonly zigDefaultBuildFlagsArray below is meant to avoid CPU feature
-# impurity in Nixpkgs. However, this flagset is "unstable": it is specifically
-# meant to be controlled by the upstream development team - being up to that
-# team exposing or not that flags to the outside (especially the package manager
-# teams).
-
-# Because of this hurdle, @andrewrk from Zig Software Foundation proposed some
-# solutions for this issue. Hopefully they will be implemented in future
-# releases of Zig. When this happens, this flagset should be revisited
-# accordingly.
-
-# Below are some useful links describing the discovery process of this 'bug' in
-# Nixpkgs:
-
-# https://github.com/NixOS/nixpkgs/issues/169461
-# https://github.com/NixOS/nixpkgs/issues/185644
-# https://github.com/NixOS/nixpkgs/pull/197046
-# https://github.com/NixOS/nixpkgs/pull/241741#issuecomment-1624227485
-# https://github.com/ziglang/zig/issues/14281#issuecomment-1624220653
-
 readonly zigDefaultFlagsArray=(@zig_default_flags@)
 
 function zigSetGlobalCacheDir {
@@ -35,7 +15,7 @@ function zigBuildPhase {
         $zigBuildFlags "${zigBuildFlagsArray[@]}"
     )
 
-    echoCmd 'build flags' "${flagsArray[@]}"
+    echoCmd 'zig build flags' "${flagsArray[@]}"
     zig build "${flagsArray[@]}"
 
     runHook postBuild
@@ -49,7 +29,7 @@ function zigCheckPhase {
         $zigCheckFlags "${zigCheckFlagsArray[@]}"
     )
 
-    echoCmd 'check flags' "${flagsArray[@]}"
+    echoCmd 'zig check flags' "${flagsArray[@]}"
     zig build test "${flagsArray[@]}"
 
     runHook postCheck
@@ -69,7 +49,7 @@ function zigInstallPhase {
         flagsArray+=("${prefixKey:---prefix}" "$prefix")
     fi
 
-    echoCmd 'install flags' "${flagsArray[@]}"
+    echoCmd 'zig install flags' "${flagsArray[@]}"
     zig build install "${flagsArray[@]}"
 
     runHook postInstall