[Patch] Fix ac_c99_complex configury

[Gabriel Dos Reis]

Paolo Carlini <pcarlini@suse.de> writes:

| Gabriel Dos Reis wrote:
| 
| >| Is this what you were implying? I think you are right WRT to the rest
| >| of the deprecated headers, at least the ones in the C++ standard under
| >| annex D. We have to keep these for the time being.
| >
| >Yes.  Let's remove complex.h.
| >  
| >
| Humm, therefore we are going to remove *only* complex.h and keep all the
| others?!? Also, I checked Annex D and, besides <strstream>, which is not
| really the point of this thread, I don't see any C++ *.h header
| mentioned. I only see the heading "Old iostreams members", notice
| *members*, which indeed we provide. Really, I'm not convinced that we
| have a sound rationale for removing complex.h and keep all the other
| backward headers.

Old iostream members refer to the classic iostreams,
i.e. <iostream.h>.  Thereis no doubt about it :-)
The reason for removing complex.h is that it leads to real clashes in
semantics with respect to C99 and we don't really need it.  I have not
seen similar reasons for other cases.  That is a sound rationale:  If it
won't break don't fix it.  <complex.h> breaks; others don't pause
maintainer problems we know of.  

-- Gaby