Work around Xcode 12.x Python interpreter.

The interpreter has a bad `-arch arm64` flag on intel that leads to
compile errors for psutil.

See: giampaolo/psutil#1832

[ci skip-rust]
[ci skip-build-wheels]

.github/workflows/test-cron.yaml

@@ -363,6 +363,7 @@ jobs:
         - 3.8.3
   test_python_macos:
     env:
+      ARCHFLAGS: -arch x86_64
       PANTS_CONFIG_FILES: +['pants.ci.toml', 'pants.remote-cache.toml']
     name: Test Python (MacOS)
     needs: bootstrap_pants_macos

.github/workflows/test.yaml

@@ -363,6 +363,7 @@ jobs:
         - 3.7.10
   test_python_macos:
     env:
+      ARCHFLAGS: -arch x86_64
       PANTS_CONFIG_FILES: +['pants.ci.toml', 'pants.remote-cache.toml']
     name: Test Python (MacOS)
     needs: bootstrap_pants_macos

build-support/bin/generate_github_workflows.py

@@ -239,7 +239,12 @@ def test_workflow_jobs(python_versions: Sequence[str]) -> Jobs:
             "runs-on": "macos-10.15",
             "needs": "bootstrap_pants_macos",
             "strategy": {"matrix": {"python-version": python_versions}},
-            "env": {**pants_config_files()},
+            "env": {
+                # Works around bad `-arch arm64` flag embedded in Xcode 12.x Python interpreters on
+                # intel machines. See: https://github.com/giampaolo/psutil/issues/1832
+                "ARCHFLAGS": "-arch x86_64",
+                **pants_config_files(),
+            },
             "steps": [
                 {"name": "Check out code", "uses": "actions/checkout@v2"},
                 *setup_primary_python(),

pants.ci.toml

@@ -26,3 +26,10 @@ ci_env_variables = [
 
 [buildsense]
 enable = true
+
+[subprocess-environment]
+env_vars.add = [
+  # Works around bad `-arch arm64` flag embedded in Xcode 12.x Python interpreters on intel
+  # machines. See: https://github.com/giampaolo/psutil/issues/1832
+  "ARCHFLAGS",
+]