Fix installation on Apple Silicon and older Python versions (#444)

Author: Takishima

CHANGELOG.md

@@ -16,6 +16,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 -   Support for Python 3.6 and earlier is now deprecated
 -   Moved package metadata into pyproject.toml
 
+### Fixed
+
+-   Fixed installation on Apple Silicon with older Python versions (< 3.9)
+
 ### Repository
 
 -   Update `docker/setup-qemu-action` GitHub action to v2

setup.py

@@ -523,6 +523,17 @@ def _configure_intrinsics(self):
             '/arch:AVX',
         ]
 
+        if int(os.environ.get('PROJECTQ_NOINTRIN', '0')) or (
+            sys.platform == 'darwin'
+            and platform.machine() == 'arm64'
+            and (sys.version_info.major == 3 and sys.version_info.minor < 9)
+        ):
+            important_msgs(
+                'Either requested no-intrinsics or detected potentially unsupported Python version on '
+                'Apple Silicon: disabling intrinsics'
+            )
+            self.compiler.define_macro('NOINTRIN')
+            return
         if os.environ.get('PROJECTQ_DISABLE_ARCH_NATIVE'):
             flags = flags[1:]