From 3ed52e5453a6971c6a3db0846f503478922d4ea5 Mon Sep 17 00:00:00 2001
From: Andrew Kelley <andrew@ziglang.org>
Date: Tue, 28 Jan 2020 14:54:34 -0500
Subject: [PATCH] fix build.zig logic for -target-cpu and -target-feature

fix a false negative for detecting the ability to emit these flags.
it matters for stage0/stage1 on aarch64
---
 lib/std/build.zig | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/lib/std/build.zig b/lib/std/build.zig
index 560f82961c..d310f53c06 100644
--- a/lib/std/build.zig
+++ b/lib/std/build.zig
@@ -1978,6 +1978,9 @@ pub const LibExeObjStep = struct {
 
                 const all_features = self.target.getArch().allFeaturesList();
                 var populated_cpu_features = cross.cpu_features.cpu.features;
+                if (self.target.getArch().subArchFeature()) |sub_arch_index| {
+                    populated_cpu_features.addFeature(sub_arch_index);
+                }
                 populated_cpu_features.populateDependencies(all_features);
 
                 if (populated_cpu_features.eql(cross.cpu_features.features)) {