From 2ededbb71ff4abce4fe63f418976417fce38105a Mon Sep 17 00:00:00 2001
From: Alex Crichton <alex@alexcrichton.com>
Date: Tue, 27 Nov 2018 21:57:36 -0800
Subject: [PATCH] Fix build of documentation in libstd

Ensure we've always got a macro defined!

Closes #603
---
 library/stdarch/coresimd/arm/armclang.rs | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/library/stdarch/coresimd/arm/armclang.rs b/library/stdarch/coresimd/arm/armclang.rs
index 39bbe3f1506f..455f911d4244 100644
--- a/library/stdarch/coresimd/arm/armclang.rs
+++ b/library/stdarch/coresimd/arm/armclang.rs
@@ -39,6 +39,13 @@ use stdsimd_test::assert_instr;
 #[inline(always)]
 #[rustc_args_required_const(0)]
 pub unsafe fn __breakpoint(val: i32) {
+    // Ensure that this compiles correctly on non-arm architectures, so libstd
+    // doc builds work. The proper macro will shadow this definition below.
+    #[allow(unused_macros)]
+    macro_rules! call {
+        ($e:expr) => {()}
+    }
+
     #[cfg(target_arch = "arm")]
     macro_rules! call {
         ($imm8:expr) => {