From 4c6546616d60c012a0839ae7f54caecaa7d6e1a7 Mon Sep 17 00:00:00 2001
From: "A. Riddell" <riddella+stan@indiana.edu>
Date: Mon, 10 Oct 2022 14:21:32 +0000
Subject: [PATCH] docs: Add note about ARCHFLAGS

---
 README.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/README.md b/README.md
index b9ccaa8..7ff78a0 100644
--- a/README.md
+++ b/README.md
@@ -12,3 +12,4 @@ GitHub Actions tries to release previously-unreleased versions of `httpstan` twi
 
 - `BUILD_COMMIT` is automatically set to the most recent tagged version of `httpstan`. See `.github/workflows/wheels.yml`.
 - `MB_PYTHON_OSX_VER=10.9` is set in `.github/workflows/wheels.yml`.
+- To avoid building universal wheels on macos, `ARCHFLAGS` is set to `-arch x86_64` in `.github/workflows/wheels.yml`. Setting `ARCHFLAGS` on macos influences what Python uses as `CFLAGS`. The httpstan `Makefile` gets `CFLAGS` from Python and uses them when compiling `httpstan/stan_services.cpp`.