https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114033
--- Comment #2 from Francois-Xavier Coudert <fxcoudert at gcc dot gnu.org> --- This is latest released version: MacOSX13.3.sdk from CLT 15.1 (on macOS 14.3). I am attaching the preprocessed source. The code from CFData.h that is triggering this is: typedef CF_OPTIONS(CFOptionFlags, CFDataSearchFlags) { kCFDataSearchBackwards = 1UL << 0, kCFDataSearchAnchored = 1UL << 1 } API_AVAILABLE(macos(10.6), ios(4.0), watchos(2.0), tvos(9.0)); which preprocesses to: typedef __attribute__((availability(swift,unavailable))) CFOptionFlags CFDataSearchFlags; enum : CFDataSearchFlags { kCFDataSearchBackwards = 1UL << 0, kCFDataSearchAnchored = 1UL << 1 } ; There is similar code linked to the error in CFString.h: typedef CF_OPTIONS(CFOptionFlags, CFStringCompareFlags) { kCFCompareCaseInsensitive = 1, kCFCompareBackwards = 4, /* Starting from the end of the string */ kCFCompareAnchored = 8, /* Only at the specified starting point */ kCFCompareNonliteral = 16, /* If specified, loose equivalence is performed (o-umlaut == o, umlaut) */ kCFCompareLocalized = 32, /* User's default locale is used for the comparisons */ kCFCompareNumerically = 64, /* Numeric comparison is used; that is, Foo2.txt < Foo7.txt < Foo25.txt */ kCFCompareDiacriticInsensitive API_AVAILABLE(macos(10.5), ios(2.0), watchos(2.0), tvos(9.0)) = 128, /* If specified, ignores diacritics (o-umlaut == o) */ kCFCompareWidthInsensitive API_AVAILABLE(macos(10.5), ios(2.0), watchos(2.0), tvos(9.0)) = 256, /* If specified, ignores width differences ('a' == UFF41) */ kCFCompareForcedOrdering API_AVAILABLE(macos(10.5), ios(2.0), watchos(2.0), tvos(9.0)) = 512 /* If specified, comparisons are forced to return either kCFCompareLessThan or kCFCompareGreaterThan if the strings are equivalent but not strictly equal, for stability when sorting (e.g. "aaa" > "AAA" with kCFCompareCaseInsensitive specified) */ };