chore: upgrade to Zig 0.16.0

.github/workflows/ci.yml

@@ -2,16 +2,16 @@ name: CI
 
 on:
   push:
-    branches: [ main ]
+    branches: [main]
   pull_request:
-    branches: [ "**" ]
+    branches: ["**"]
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}-ci
   cancel-in-progress: true
 
 env:
-  ZIG_VERSION: 0.14.1
+  ZIG_VERSION: 0.16.0
 
 jobs:
   build-test:
@@ -20,7 +20,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ ubuntu-latest, macos-latest, windows-latest ]
+        os: [ubuntu-latest, macos-latest, windows-latest]
 
     steps:
       - uses: actions/checkout@v4

.gitignore

@@ -1,2 +1,3 @@
-.zig-cache
-zig-out
+.zig-cache/
+zig-out/
+zig-pkg/

build.zig

@@ -8,15 +8,15 @@ pub fn build(b: *std.Build) !void {
 
     const upstream = b.dependency("blst", .{});
 
-    var c_flags = std.ArrayList([]const u8).init(b.allocator);
-    defer c_flags.deinit();
+    var c_flags = std.ArrayList([]const u8).empty;
+    defer c_flags.deinit(b.allocator);
 
-    try c_flags.append("-fno-builtin");
-    try c_flags.append("-Wno-unused-function");
-    try c_flags.append("-Wno-unused-command-line-argument");
+    try c_flags.append(b.allocator, "-fno-builtin");
+    try c_flags.append(b.allocator, "-Wno-unused-function");
+    try c_flags.append(b.allocator, "-Wno-unused-command-line-argument");
 
     if (target.result.cpu.arch == .x86_64) {
-        try c_flags.append("-mno-avx"); // avoid costly transitions
+        try c_flags.append(b.allocator, "-mno-avx"); // avoid costly transitions
     }
 
     const lib = b.addLibrary(.{
@@ -33,7 +33,15 @@ pub fn build(b: *std.Build) !void {
     if (portable) {
         lib.root_module.addCMacro("__BLST_PORTABLE__", "");
     } else {
-        if (std.Target.x86.featureSetHas(target.result.cpu.features, .adx)) {
+        // Guard __ADX__ check to x86_64 only.
+        // std.Target.x86.featureSetHas on non-x86 cpu features is meaningless —
+        // the feature indices differ per-arch and may accidentally return true
+        // for unrelated ARM features, incorrectly defining __ADX__ and breaking
+        // symbol resolution (server.c then references ctx_* symbols that don't
+        // exist in the mach-o/elf ARM64 assembly).
+        if (target.result.cpu.arch == .x86_64 and
+            std.Target.x86.featureSetHas(target.result.cpu.features, .adx))
+        {
             lib.root_module.addCMacro("__ADX__", "");
         }
     }
@@ -45,10 +53,11 @@ pub fn build(b: *std.Build) !void {
     {
         lib.root_module.addCMacro("__BLST_NO_ASM__", "");
     }
+
     lib.installHeader(upstream.path("bindings/blst.h"), "blst.h");
     lib.installHeader(upstream.path("bindings/blst_aux.h"), "blst_aux.h");
 
-    lib.addCSourceFiles(.{
+    lib.root_module.addCSourceFiles(.{
         .root = upstream.path(""),
         .files = &.{
             "src/server.c",

build.zig.zon

@@ -5,7 +5,7 @@
 
     .fingerprint = 0x97ffb139ce317072, // Changing this has security and trust implications.
 
-    .minimum_zig_version = "0.14.1",
+    .minimum_zig_version = "0.16.0",
 
     .dependencies = .{
         .blst = .{