[PATCH] D64482: [Driver] Define _FILE_OFFSET_BITS=64 on Solaris

[Rainer Orth via Phabricator via cfe-commits]

ro added a comment.

In D64482#1588154 <https://reviews.llvm.org/D64482#1588154>, @rnk wrote:

> > To avoid a similar inconsistence with host compilers that don't predefine _FILE_OFFSET_BITS=64
> >  (e.g. clang < 9, gcc < 9), this needs a compantion patch to be submitted shortly.
>
> I'm curious, what's the plan for that? I suppose the user can always take things into their own hands with -D and -U.


The companion patch https://reviews.llvm.org/D64483 unconditionally predefines `_FILE_OFFSET_BITS=64` on Solaris, irrespective
of compiler.  It still needs approval and should go in first, otherwise we trade the failure with a gcc 9 host compiler for a failure with 
older gcc and clang (and this also would break the Solaris buildbots, which currently use gcc 7).

While users could use -D/-U by themselves to select the largefile support they want, I wouldn't rely too much on that, with parts of
libstdc++ in headers and the rest in the shared object.  Mixing code with and without largefile support in the same executable works,
of course, but the results may be surprising...


Repository:
  rC Clang

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  https://reviews.llvm.org/D64482/new/

https://reviews.llvm.org/D64482