build: add rust target for macOS cross compiles

When we build the macOS pkg, we build Node.js twice (on arm64):
- Once for arm64 (native)
- Once for x64, using a combination of Rosetta 2 and compiler flags

before combining both into a universal binary.

For the x64 case, pass target flag to `rustc` so that the binary is
built for the correct target architecture.

Signed-off-by: Richard Lau <[email protected]>

Author: richardlau

configure.py

@@ -1855,6 +1855,10 @@ def configure_node(o):
   if flavor == 'win':
     o['variables']['cargo_rust_target'] = \
       'aarch64-pc-windows-msvc' if target_arch == 'arm64' else 'x86_64-pc-windows-msvc'
+  # Always set the Rust target for x64 macOS in case we will be building
+  # under Rosetta 2.
+  if flavor == 'mac' and target_arch == 'x64':
+    o['variables']['cargo_rust_target'] = 'x86_64-apple-darwin'
 
   # Allow overriding the compiler - needed by embedders.
   if options.use_clang:

deps/crates/crates.gyp

@@ -11,12 +11,17 @@
       },
       'conditions': [
         ['cargo_rust_target!=""', {
+          'variables': {
+            'cargo_build_flags': ['--target', '<(cargo_rust_target)'],
+          }
+        }],
+        ['OS=="win"', {
           'variables': {
             'node_crates_libpath': '<(SHARED_INTERMEDIATE_DIR)/$(Platform)/release/node_crates.lib',
           },
         }, {
           'variables': {
-            'node_crates_libpath': '<(SHARED_INTERMEDIATE_DIR)/release/<(STATIC_LIB_PREFIX)node_crates<(STATIC_LIB_SUFFIX)',
+            'node_crates_libpath': '<(SHARED_INTERMEDIATE_DIR)/<(cargo_rust_target)/release/<(STATIC_LIB_PREFIX)node_crates<(STATIC_LIB_SUFFIX)',
           },
         }],
       ],
@@ -25,13 +30,13 @@
         'cargo_build_flags': [],
       },
       'conditions': [
-        ['cargo_rust_target!=""', {
+        ['OS=="win"', {
           'variables': {
             'node_crates_libpath': '<(SHARED_INTERMEDIATE_DIR)/$(Platform)/debug/node_crates.lib',
           },
         }, {
           'variables': {
-            'node_crates_libpath': '<(SHARED_INTERMEDIATE_DIR)/debug/<(STATIC_LIB_PREFIX)node_crates<(STATIC_LIB_SUFFIX)',
+            'node_crates_libpath': '<(SHARED_INTERMEDIATE_DIR)/<(cargo_rust_target)/debug/<(STATIC_LIB_PREFIX)node_crates<(STATIC_LIB_SUFFIX)',
           },
         }],
       ],
@@ -62,7 +67,7 @@
         ],
       },
       'conditions': [
-        ['cargo_rust_target!=""', {
+        ['OS=="win"', {
           'actions': [
             {
               'action_name': 'cargo_build',