Latest macOS system header causes compilation failures on GCC about catch2

[horenmar]

Why does the compilation fail there? Is this a hard error?

[morinmorin]

Yes, that's hard errors. For example, on mac with the latest developer tools, this

echo '#include <catch2/catch_all.hpp>' | g++-13 -xc++ -

produces the following error messages

In file included from catch2/internal/catch_platform.hpp:14,
                 from catch2/internal/catch_compiler_capabilities.hpp:27,
                 from catch2/benchmark/catch_benchmark.hpp:14,
                 from catch2/benchmark/catch_benchmark_all.hpp:24,
                 from catch2/catch_all.hpp:25,
                 from <stdin>:1:
/usr/include/TargetConditionals.h:140:50: error: missing binary operator before token "("
  140 | #if !defined(__has_extension) || !__has_extension(define_target_os_macros)

The code !__has_extension(define_target_os_macros) causes compilation failure, because __has_extension is not supported/defined on GCC (until the next release of GCC).

[horenmar]

Hmmm, yeah there was a reason why we are checking headers like this

#if defined(__has_include)
  #if __has_include(<string_view>) && defined(CATCH_CPP17_OR_GREATER)

I'll accept a PR that adds the workaround.

[morinmorin]

Thanks. I'll submit PR later.