[Patch] Fix ac_c99_complex configury

[Gabriel Dos Reis]

Paolo Carlini <pcarlini@suse.de> writes:

| Speaking of questions: what about my question regarding
| include/backward? Are your customers still including <iostream.h>? Tell
| me not ;)

well, I can tell you I continue to see people #include <iostream.h> no
matter what we say here.  I don't think it would be a wise move to
remove it. 

-- Gaby