zig: backport an upstream bugfix

This commit backports one bug fix from the zig master branch which is
critical for our use-case of building software for binary distribution.

srcpkgs/zig/patches/0001-std.build-fix-handling-of-Dcpu.patch

@@ -0,0 +1,48 @@
+From 1e8cdace7ad324a42228aeb5cd6eb8dd15429413 Mon Sep 17 00:00:00 2001
+From: Isaac Freund <ifreund@ifreund.xyz>
+Date: Tue, 21 Sep 2021 21:06:10 +0200
+Subject: [PATCH] std.build: fix handling of -Dcpu
+
+Currently -Dcpu is completely ignored if -Dtarget isn't passed as well.
+Further, -Dcpu=baseline is ignored even if -Dtarget=native is passed.
+
+This patch fixes these 2 issues, always respecting the -Dcpu option if
+present.
+---
+ lib/std/build.zig | 13 +++++++------
+ 1 file changed, 7 insertions(+), 6 deletions(-)
+
+diff --git a/lib/std/build.zig b/lib/std/build.zig
+index 9b7ebb1f4..e398529f9 100644
+--- a/lib/std/build.zig
++++ b/lib/std/build.zig
+@@ -685,7 +685,11 @@ pub const Builder = struct {
+         );
+         const mcpu = self.option([]const u8, "cpu", "Target CPU");
+ 
+-        const triple = maybe_triple orelse return args.default_target;
++        if (maybe_triple == null and mcpu == null) {
++            return args.default_target;
++        }
++
++        const triple = maybe_triple orelse "native";
+ 
+         var diags: CrossTarget.ParseOptions.Diagnostics = .{};
+         const selected_target = CrossTarget.parse(.{
+@@ -2451,11 +2455,8 @@ pub const LibExeObjStep = struct {
+ 
+             if (populated_cpu_features.eql(cross.cpu.features)) {
+                 // The CPU name alone is sufficient.
+-                // If it is the baseline CPU, no command line args are required.
+-                if (cross.cpu.model != std.Target.Cpu.baseline(cross.cpu.arch).model) {
+-                    try zig_args.append("-mcpu");
+-                    try zig_args.append(cross.cpu.model.name);
+-                }
++                try zig_args.append("-mcpu");
++                try zig_args.append(cross.cpu.model.name);
+             } else {
+                 var mcpu_buffer = std.ArrayList(u8).init(builder.allocator);
+ 
+-- 
+2.33.1
+

srcpkgs/zig/template

@@ -1,13 +1,13 @@
 # Template file for 'zig'
 pkgname=zig
 version=0.8.1
-revision=1
+revision=2
 archs="x86_64* aarch64*"
 build_style=cmake
 make_cmd=make
 makedepends="clang llvm12 lld-devel"
 short_desc="Programming language designed for robustness, optimality, and clarity"
-maintainer="Isaac Freund <ifreund@ifreund.xyz>"
+maintainer="Isaac Freund <mail@isaacfreund.com>"
 license="MIT"
 homepage="https://ziglang.org"
 distfiles="https://ziglang.org/download/${version}/zig-${version}.tar.xz"