[PATCH][_GLIBCXX_INLINE_VERSION] Fix <contracts>

[Iain Sandoe]

Hi François,

> On 21 Sep 2023, at 05:41, François Dumont <frs.dumont@gmail.com> wrote:
> 
> Tests were successful, ok to commit ?
> 
> On 20/09/2023 19:51, François Dumont wrote:
>> libstdc++: [_GLIBCXX_INLINE_VERSION] Add handle_contract_violation symbol alias
>> 
>> libstdc++-v3/ChangeLog:
>> 
>>     * src/experimental/contract.cc
>>     [_GLIBCXX_INLINE_VERSION](handle_contract_violation): Provide symbol alias
>>     without version namespace decoration for gcc.

This does not work in the source on targets without support for symbol aliases (Darwin is one)
“../experimental/contract.cc:79:8: warning: alias definitions not supported in Mach-O; ignored”

- there might be a way to do it at link-time (for one symbol not too bad); I will have to poke at
  it a bit.
Iain

>> 
>> Here is what I'm testing eventually, ok to commit if successful ?
>> 
>> François
>> 
>> On 20/09/2023 11:32, Jonathan Wakely wrote:
>>> On Wed, 20 Sept 2023 at 05:51, François Dumont via Libstdc++
>>> <libstdc++@gcc.gnu.org> wrote:
>>>> libstdc++: Remove std::constract_violation from versioned namespace
>>> Spelling mistake in contract_violation, and it's not
>>> std::contract_violation, it's std::experimental::contract_violation
>>> 
>>>> GCC expects this type to be in std namespace directly.
>>> Again, it's in std::experimental not in std directly.
>>> 
>>> Will this change cause problems when including another experimental
>>> header, which does put experimental below std::__8?
>>> 
>>> I think std::__8::experimental and std::experimental will become ambiguous.
>>> 
>>> Maybe we do want to remove the inline __8 namespace from all
>>> experimental headers. That needs a bit more thought though.
>>> 
>>>> libstdc++-v3/ChangeLog:
>>>> 
>>>>       * include/experimental/contract:
>>>>       Remove _GLIBCXX_BEGIN_NAMESPACE_VERSION/_GLIBCXX_END_NAMESPACE_VERSION.
>>> This line is too long for the changelog.
>>> 
>>>> It does fix 29 g++.dg/contracts in gcc testsuite.
>>>> 
>>>> Ok to commit ?
>>>> 
>>>> François