conflict between libstdc++ nan and c99/builtin nan functions

["Kaveh R. Ghazi" <ghazi at caip dot rutgers dot edu>]

I'm getting this warning (several times) when building libstdc++-v3:

 > libstdc++-v3/libmath/mathconf.h:84: warning: conflicting types for
 > built-in function `nan'

mathconf.h contains:

 > #ifndef NAN
 > # define NAN (nan())
 > double nan (void);
 > #endif

The definition of libstdc++-v3's `nan' in libmath/nan.c is:

 > double nan ()
 > { return strtod ("nan", NULL); }


whereas the builtin is defined as:

 > double nan (const char *);


Checking:
http://www.opengroup.org/onlinepubs/007904975/functions/nan.html it
appears that the builtin is correct.


My question is whether libstdc++-v3 needs to provide `nan' as an
exportable function or whether it just needs it internally.  If it's
just internally, perhaps I can change the NAN macro to just call
__builtin_nan(""), otherwise I'll correct the definition in nan.c.

		Thanks,
		--Kaveh
--
Kaveh R. Ghazi			ghazi@caip.rutgers.edu