Update shell.nix to nixpkgs-24.05 and LLVM 18

.github/workflows/macos.yml

@@ -11,18 +11,21 @@ concurrency:
 env:
   SPEC_SPLIT_DOTS: 160
   CI_NIX_SHELL: true
+  CRYSTAL_OPTS: -Dwithout_iconv
 
 jobs:
   darwin-test:
     runs-on: ${{ matrix.runs-on }}
     name: ${{ matrix.arch }}
     strategy:
+      fail-fast: false
       matrix:
         include:
         - runs-on: macos-13
           arch: x86_64-darwin
         - runs-on: macos-14
           arch: aarch64-darwin
+
     steps:
       - name: Download Crystal source
         uses: actions/checkout@v4

bin/ci

@@ -213,6 +213,7 @@ with_build_env() {
     -e CRYSTAL_CACHE_DIR="/tmp/crystal" \
     -e SPEC_SPLIT_DOTS \
     -e USE_PCRE1 \
+    -e CRYSTAL_OPTS \
     "$DOCKER_TEST_IMAGE" \
     "$ARCH_CMD" /bin/sh -c "'$command'"
 
@@ -222,7 +223,7 @@ with_build_env() {
     CRYSTAL_CACHE_DIR="/tmp/crystal" \
     /bin/sh -c "'$command'"
 
-  on_nix_shell nix-shell --pure $CI_NIX_SHELL_ARGS --run "'TZ=$TZ $command'"
+  on_nix_shell nix-shell --pure $CI_NIX_SHELL_ARGS --keep CRYSTAL_OPTS --run "'TZ=$TZ $command'"
 
   on_github echo "::endgroup::"
 }

shell.nix

@@ -19,13 +19,13 @@
 # $ nix-shell --pure --arg musl true
 #
 
-{llvm ? 11, musl ? false, system ? builtins.currentSystem}:
+{llvm ? 18, musl ? false, system ? builtins.currentSystem}:
 
 let
   nixpkgs = import (builtins.fetchTarball {
-    name = "nixpkgs-23.05";
-    url = "https://github.com/NixOS/nixpkgs/archive/23.05.tar.gz";
-    sha256 = "10wn0l08j9lgqcw8177nh2ljrnxdrpri7bp0g7nvrsn9rkawvlbf";
+    name = "nixpkgs-24.05";
+    url = "https://github.com/NixOS/nixpkgs/archive/24.05.tar.gz";
+    sha256 = "1lr1h35prqkd1mkmzriwlpvxcb34kmhc9dnr48gkm8hh089hifmx";
   }) {
     inherit system;
   };