arrow: Fix cross-compiling errors on macos

cmake/toolchains/darwin-arm64.cmake

@@ -0,0 +1,24 @@
+#  ┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
+#  ┃ ██████ ██████ ██████       █      █      █      █      █ █▄  ▀███ █       ┃
+#  ┃ ▄▄▄▄▄█ █▄▄▄▄▄ ▄▄▄▄▄█  ▀▀▀▀▀█▀▀▀▀▀ █ ▀▀▀▀▀█ ████████▌▐███ ███▄  ▀█ █ ▀▀▀▀▀ ┃
+#  ┃ █▀▀▀▀▀ █▀▀▀▀▀ █▀██▀▀ ▄▄▄▄▄ █ ▄▄▄▄▄█ ▄▄▄▄▄█ ████████▌▐███ █████▄   █ ▄▄▄▄▄ ┃
+#  ┃ █      ██████ █  ▀█▄       █ ██████      █      ███▌▐███ ███████▄ █       ┃
+#  ┣━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┫
+#  ┃ Copyright (c) 2017, the Perspective Authors.                              ┃
+#  ┃ ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ ┃
+#  ┃ This file is part of the Perspective library, distributed under the terms ┃
+#  ┃ of the [Apache License 2.0](https://www.apache.org/licenses/LICENSE-2.0). ┃
+#  ┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛
+
+# Minimal toolchain file to ensure that Arrow's bundled dependency builds use
+# the correct architecture for Mac builds.
+
+# (Arrow does not as of Oct 2024 pass on CMAKE_OSX_ARCHITECTURES to its
+# dependencies if it is set, but does pass on a toolchain file)
+
+set(CMAKE_OSX_ARCHITECTURES "arm64" CACHE STRING "Target architecture for Mac builds")
+# Arrow uses this to choose a `-march` flag
+set(CMAKE_SYSTEM_PROCESSOR "arm64")
+# Prevent cmake from overwriting CMAKE_SYSTEM_PROCESSOR
+# https://github.com/apache/arrow/issues/44448#issuecomment-2418649378
+set(CMAKE_SYSTEM_NAME "Darwin")

cmake/toolchains/darwin-x86_64.cmake

@@ -0,0 +1,24 @@
+#  ┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
+#  ┃ ██████ ██████ ██████       █      █      █      █      █ █▄  ▀███ █       ┃
+#  ┃ ▄▄▄▄▄█ █▄▄▄▄▄ ▄▄▄▄▄█  ▀▀▀▀▀█▀▀▀▀▀ █ ▀▀▀▀▀█ ████████▌▐███ ███▄  ▀█ █ ▀▀▀▀▀ ┃
+#  ┃ █▀▀▀▀▀ █▀▀▀▀▀ █▀██▀▀ ▄▄▄▄▄ █ ▄▄▄▄▄█ ▄▄▄▄▄█ ████████▌▐███ █████▄   █ ▄▄▄▄▄ ┃
+#  ┃ █      ██████ █  ▀█▄       █ ██████      █      ███▌▐███ ███████▄ █       ┃
+#  ┣━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┫
+#  ┃ Copyright (c) 2017, the Perspective Authors.                              ┃
+#  ┃ ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ ┃
+#  ┃ This file is part of the Perspective library, distributed under the terms ┃
+#  ┃ of the [Apache License 2.0](https://www.apache.org/licenses/LICENSE-2.0). ┃
+#  ┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛
+
+# Minimal toolchain file to ensure that Arrow's bundled dependency builds use
+# the correct architecture for Mac builds.
+
+# (Arrow does not as of Oct 2024 pass on CMAKE_OSX_ARCHITECTURES to its
+# dependencies if it is set, but does pass on a toolchain file)
+
+set(CMAKE_OSX_ARCHITECTURES "x86_64" CACHE STRING "Target architecture for Mac builds")
+# Arrow uses this to choose a `-march` flag
+set(CMAKE_SYSTEM_PROCESSOR "x86_64")
+# Prevent cmake from overwriting CMAKE_SYSTEM_PROCESSOR
+# https://github.com/apache/arrow/issues/44448#issuecomment-2418649378
+set(CMAKE_SYSTEM_NAME "Darwin")

rust/perspective-server/build/psp.rs

@@ -26,10 +26,24 @@ pub fn cmake_build() -> Result<Option<PathBuf>, std::io::Error> {
     let profile = std::env::var("PROFILE").unwrap();
     dst.always_configure(true);
     dst.define("CMAKE_BUILD_TYPE", profile.as_str());
-    if std::env::var("PSP_ARCH").as_deref() == Ok("x86_64") {
-        dst.define("CMAKE_OSX_ARCHITECTURES", "x86_64");
-    } else if std::env::var("PSP_ARCH").as_deref() == Ok("arm64") {
-        dst.define("CMAKE_OSX_ARCHITECTURES", "arm64");
+
+    if cfg!(target_os = "macos") {
+        // Set CMAKE_OSX_ARCHITECTURES et al. for Mac builds.  Arrow does not forward on
+        // CMAKE_OSX_ARCHITECTURES and but it does forward on a
+        // CMAKE_TOOLCHAIN_FILE. In Conda builds, the environment sets
+        // `CMAKE_ARGS` up with various toolchain arguments. This block may need
+        // to be patched out or adjusted for Conda.
+        let toolchain_file = match std::env::var("PSP_ARCH").as_deref() {
+            Ok("x86_64") => "./cmake/toolchains/darwin-x86_64.cmake",
+            Ok("aarch64") => "./cmake/toolchains/darwin-arm64.cmake",
+            arch @ Ok(_) | arch @ Err(_) => {
+                panic!("Unknown PSP_ARCH value: {:?}", arch)
+            },
+        };
+        dst.define(
+            "CMAKE_TOOLCHAIN_FILE",
+            std::fs::canonicalize(toolchain_file).expect("Failed to canonicalize toolchain file."),
+        );
     }
 
     if std::env::var("TARGET")