mac: Don't even call 'sw_vers -buildVersion'

This should've been in
https://chromium-review.googlesource.com/c/chromium/src/+/2540578

Bug: 1149401
Change-Id: Ia6d7edb033064a5a953625a51266fd8cb3051d33
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2541805
Auto-Submit: Nico Weber <thakis@chromium.org>
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#827917}

build/config/ios/ios_sdk.gni

@@ -127,7 +127,10 @@ if (ios_sdk_path == "") {
     assert(false, "unsupported environment: $target_environment")
   }
 
-  ios_sdk_info_args = [ "--get_sdk_info" ]
+  ios_sdk_info_args = [
+    "--get_sdk_info",
+    "--get_machine_info",
+  ]
   ios_sdk_info_args += [ ios_sdk_name ]
   if (ios_sdk_developer_dir != "") {
     ios_sdk_info_args += [

build/config/mac/mac_sdk.gni

@@ -89,7 +89,6 @@ sdk_info_args += [ mac_sdk_name ]
 _mac_sdk_result = exec_script(script_name, sdk_info_args, "scope")
 xcode_version = _mac_sdk_result.xcode_version
 xcode_build = _mac_sdk_result.xcode_build
-machine_os_build = _mac_sdk_result.machine_os_build
 if (mac_sdk_path == "" && use_system_xcode && ios_use_goma_rbe) {
   mac_sdk_path = _mac_sdk_result.sdk_path
 }

build/config/mac/sdk_info.py

@@ -128,8 +128,15 @@ if __name__ == '__main__':
   parser = argparse.ArgumentParser()
   parser.add_argument("--developer_dir", dest="developer_dir", required=False)
   parser.add_argument("--get_sdk_info",
-                    action="store_true", dest="get_sdk_info", default=False,
-                    help="Returns SDK info in addition to xcode/machine info.")
+                      action="store_true",
+                      dest="get_sdk_info",
+                      default=False,
+                      help="Returns SDK info in addition to xcode info.")
+  parser.add_argument("--get_machine_info",
+                      action="store_true",
+                      dest="get_machine_info",
+                      default=False,
+                      help="Returns machine info in addition to xcode info.")
   parser.add_argument(
       "--create_symlink_at",
       action="store",
@@ -148,7 +155,8 @@ if __name__ == '__main__':
     sys.exit(1)
 
   settings = {}
-  FillMachineOSBuild(settings)
+  if args.get_machine_info:
+    FillMachineOSBuild(settings)
   FillXcodeVersion(settings, args.developer_dir)
   if args.get_sdk_info:
     FillSDKPathAndVersion(settings, unknownargs[0], settings['xcode_version'])