Added --apple_platforms command line argument to Bazel.

Not currently used by any rules. This will require forthcoming changes to the Apple split transition before it can begin to be useful.

PiperOrigin-RevId: 388809149

src/main/java/com/google/devtools/build/lib/rules/apple/AppleCommandLineOptions.java

@@ -384,6 +384,17 @@ public class AppleCommandLineOptions extends FragmentOptions {
               + " option may be provided multiple times.")
   public List<Map.Entry<ApplePlatform.PlatformType, AppleBitcodeMode>> appleBitcodeMode;
 
+  // TODO(b/180572694): Modify the Apple split transition to split the --apple_platforms out into a
+  // single --platform during the transition instead of splitting on the --*_cpus flags.
+  @Option(
+      name = "apple_platforms",
+      converter = CommaSeparatedOptionListConverter.class,
+      defaultValue = "null",
+      documentationCategory = OptionDocumentationCategory.UNDOCUMENTED,
+      effectTags = {OptionEffectTag.LOSES_INCREMENTAL_STATE, OptionEffectTag.LOADING_AND_ANALYSIS},
+      help = "Comma-separated list of platforms to use when building Apple binaries.")
+  public List<String> applePlatforms;
+
   /** Returns whether the minimum OS version is explicitly set for the current platform. */
   public DottedVersion getMinimumOsVersion() {
     DottedVersion.Option option;