-Wignored-attributes error with old clang

[sezero]

With clang 3.4.2, I got the following error:

In file included from /tmp/libavif/src/alpha.c:4:
In file included from /tmp/libavif/include/avif/internal.h:7:
/tmp/libavif/include/avif/avif.h:157:14: error: 'warn_unused_result' attribute only applies to functions, methods, and classes [-Werror,-Wignored-attributes]
typedef enum AVIF_NODISCARD avifResult
             ^
/tmp/libavif/include/avif/avif.h:57:39: note: expanded from macro 'AVIF_NODISCARD'
#define AVIF_NODISCARD __attribute__((warn_unused_result))
                                      ^
1 error generated.

Seems to be after #1655

Removing AVIF_NODISCARD from avifResult enum makes the build to succeed.

[y-guyon]

Thanks for the report.

Does setting -DAVIF_ENABLE_WERROR=OFF solve the issue?

[sezero]

Yes, it does for build of libavif itself. (The thing is though, the public header is the offender.)

[vrabaud]

Using godbolt, I could figure out clang 3.9.0 was the first one to introduce the behavior for enums.