message: [vcpkg] Fix unrecognized identifier errors in prbuild and cibuild.
diff: @@ -29,6 +29,7 @@ namespace vcpkg::PlatformExpression
  uwp,
  android,
  emscripten,
  + ios,
  static_link,
  };
  @@ -48,6 +49,7 @@ namespace vcpkg::PlatformExpression
  {"uwp", Identifier::uwp},
  {"android", Identifier::android},
  {"emscripten", Identifier::emscripten},
  + {"ios", Identifier::ios},
  {"static", Identifier::static_link},
  };
  @@ -392,6 +394,7 @@ namespace vcpkg::PlatformExpression
  case Identifier::android: return true_if_exists_and_equal("VCPKG_CMAKE_SYSTEM_NAME", "Android");
  case Identifier::emscripten:
  return true_if_exists_and_equal("VCPKG_CMAKE_SYSTEM_NAME", "Emscripten");
  + case Identifier::ios: return true_if_exists_and_equal("VCPKG_CMAKE_SYSTEM_NAME", "iOS");
  case Identifier::wasm32: return true_if_exists_and_equal("VCPKG_TARGET_ARCHITECTURE", "wasm32");
  case Identifier::static_link:
  return true_if_exists_and_equal("VCPKG_LIBRARY_LINKAGE", "static");
  