https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90835
Bug ID: 90835
Summary: Incompatibilities with macOS 10.15 headers
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: ro at gcc dot gnu.org
CC: iains at gcc dot gnu.org
Target Milestone: ---
Host: x86_64-apple-darwin19
Target: x86_64-apple-darwin19
Build: x86_64-apple-darwin19
Once the issues from PR target/90834 are worked around or fixed, there remain
a couple of bugs in the macOS 10.15/Xcode 11 headers that make them
incompatible
with gcc, breaking the gcc build.
While I mean to report them to Apple, I'm reporting them here either for others
who want to try the same build or in case they aren't fixed upstream in time.
* <Availability.h> lacks fallback definitions of __OSX_AVAILABLE_STARTING and
friends if the availability attribute isn't supported (as in gcc, unlike
clang).
* <AvailabilityInternal.h> unconditionally uses __has_builtin. Besides, the
fixes for lack of the availability attribute in __API_[ADU] are still needed.
Probably nobody reported them upstream, or perhaps Apple decided to ignore
the
report?
* <mach-o/dyld.h> unconditionally uses the availability attribute. Just
commenting
those uses as I've done is a hack; probably there another weird macro in
<Availability*.h> that's cleaner here.
* <TargetConditionals.h> unconditionally uses __has_builtin.
With those patches, I managed to complete a mainline bootstrap on Darwin 19;
make check still running.
