Compiler baselines

[Stephan Bergmann]

On 13/09/2018 12:21, Stephan Bergmann wrote:
> * On macOS, our baseline is Xcode 8 according to 
> <https://cgit.freedesktop.org/libreoffice/core/commit/?id=1079893be5593268eff0867be87b0291546d88c7> 
> "Document baselines".  According to 
> <https://en.wikipedia.org/wiki/Xcode#Latest_versions> that means the 
> oldest Apple Clang we need to support corresponds roughly to Clang 3.9. 
> (Unfortunately, the information about what plain Clang the Apple Clang 
> shipped with Xcode corresponds to ends with Xcode 8.2.1 at 
> <https://en.wikipedia.org/wiki/Xcode#Latest_versions>, so it is not 
> immediately clear what benefit any update of our Xcode baseline would 
> bring us Clang-version wise.)

as found on #libreoffice-dev:

> Sep 14 11:18:53 <buovjaga>	sberg: I found a community of alchemists specialising in deciphering Apple's clang strategy. The latest comments are informative: https://gist.github.com/yamaya/2924292#gistcomment-2683289
> Sep 14 11:19:11 <buovjaga>	"One particularly informative header is libc++'s __config which defines the _LIBCPP_VERSION macro. For 9.1.0 it is 5000 which suggests it is from somewhere in the 5-series line. While for 10.0.0 (from Beta 6) it is 6000."