Re: confdefs.h not being included by AC_LANG_SOURCE()

[Brian J. Murrell]

On Tue, 2010-03-02 at 15:48 -0700, Eric Blake wrote: 
> The change was made back on 2008-11-03 (commit 8e27cc7f5, contained in
> autoconf 2.63b), so although it is somewhat of a regression
> (AC_LANG_CONFTEST outputs defines now, when it did not do so previously),
> there obviously aren't that many packages that try to mix-and-match their
> own LANG_CONFTEST with autoconf's LANG_SOURCE, or we might have heard
> about this issue sooner.

Indeed,

> May I ask why LB_LANG_CONFTEST was created in the first place,

Don't really know, TBH.  Hysterical raisins I am sure.

> rather than
> sticking with the autoconf interface, or is that decision lost in history?

Yeah.  I asked around.  Nobody seemed to know, or speak up if they did.
I am going to run some tests to see if we can simply use
AC_LANG_CONFTEST and be done with the issue.  I'd prefer to use as much
upstream work as I can (hence my queries about contributing linux kernel
tests and macros).  I always do.  Less surprises like this when you can.

> Might it have something to do with the (ancient) bug where we tried to
> output #line directives in the original conftest file corresponding to
> locations in configure, which was later withdrawn when it was determined
> that configure files often exceed 64k lines and it breaks some
> preprocessors to have #line numbers that large?

Could be, but I really have no idea.

b.

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