Re: MacOS 64-bit build

[Hans Åberg]

> On 9 Jan 2020, at 13:34, Werner LEMBERG <address@hidden> wrote:
> 
>> `configure` should warn or bail on incompatible flex versions.  I
>> suggest we add a version check in configure.ac to ensure that flex
>> version is between 2.5.37 and 2.5.39 (given that 2.5.38 and 2.5.39
>> actually works).
> 
> What you suggest wouldn't work as expected.  There is no guarantee
> that `FlexLexer.h` found during compilation is the one that is used by
> a recent flex version.  Unfortunately, `FlexLexer.h` doesn't contain
> any version information, so it is really impossible to protect against
> this situation automatically.

Akim Demaille made a patch for it, see:
https://lists.gnu.org/archive/html/bug-bison/2018-09/msg00020.html