[v3] Use Solaris prototypes if possible (PR libstdc++-v3/1773)

[Marc Glisse]

On Tue, 9 Aug 2011, Rainer Orth wrote:

> This patch is the last but one in the series to finally fix
>
> PR libstdc++-v3/1773	__cplusplus defined to 1, should be 199711L

Only piece left before the switch :-)

> 	* include/c_global/cmath (double abs(double)): Wrap in
> 	!__CORRECT_ISO_CPP_MATH_H_PROTO1 &&
> 	!__CORRECT_ISO_CPP_MATH_H_PROTO2.
> 	(float abs(float), long double abs(long double): Wrap in
> 	!__CORRECT_ISO_CPP_MATH_H_PROTO1.
> 	(float acos(float), long double acos(long double)): Likewise.
[...]

I guess it would also be possible to reorder the declarations so as to 
have a single #ifdef (well, two), but then the various overloads of each 
function wouldn't be adjacent anymore.

> 	* include/tr1/cmath (float fabs(float), long double fabs(long
> 	double)): Wrap in !__CORRECT_ISO_CPP_MATH_H_PROTO1.

There is a comment:
   // Note: we deal with fabs in a special way, because an using std::fabs
   // would bring in also the overloads for complex types, which in C++0x
   // mode have a different return type.

and then it proceeds to using ::fabs and declare the float and long double 
overloads. Now on solaris, using ::fabs is going to be equivalent to using 
std::fabs. I don't know if that creates problems for the complex types, 
and in that case what can be done about it (declare fabs(double) instead 
of importing the global one?).

-- 
Marc Glisse