[Bug c++/26989] C++ front-end (and others parts of GCC) use the wrong check to see if hidden visibility is there

[iains at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=26989

--- Comment #8 from Iain Sandoe <iains at gcc dot gnu.org> ---
(In reply to Jonathan Wakely from comment #7)
> Cc Iain who probably knows more about the Darwin linker. I'm pretty sure it
> supports visibility now because LLVM's libc++ makes extensive use of
> visibility attributes.

hmm... Darwin7 ...

Well... as things stand Darwin7 will not bootstrap even gcc-4.6 with its system
toolchain [xcode 1.5] (it fails very early with "make is too old") I haven't
figured a recipe for the minimum number of tools that need to be upgraded yet
(and it's frankly very low priority).

====

However, that being said - we should verify that the test is appropriate to
newer systems too (or even still exists?)