[Bug libstdc++/79017] Old PowerMac G5, MacPorts GCC 5.4, C++11 and "std::log2 has not been declared"

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79017

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2017-01-06
     Ever confirmed|0                           |1

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Jeffrey Walton from comment #0)
> test.cxx:53:21: error: 'llrint' was not declared in this scope
>            llrint(0.0);
>                      ^
> test.cxx:54:23: error: 'llrintf' was not declared in this scope
>            llrintf(0.0f);
>                        ^
> test.cxx:55:23: error: 'llrintl' was not declared in this scope
>            llrintl(0.0l);
>                        ^
> test.cxx:56:22: error: 'llround' was not declared in this scope
>            llround(0.0);
>                       ^
> test.cxx:57:24: error: 'llroundf' was not declared in this scope
>            llroundf(0.0f);
>                         ^
> test.cxx:58:24: error: 'llroundl' was not declared in this scope
>            llroundl(0.0l);
>                         ^

Because these six functions are missing we treat all C99 math functions as
missing. We could split the checks into two pieces, so we check for these
separately, which would allow the rest of the C99 math library to be imported
into namespace std.

But OS X 10.5.8 is pretty old, and this might not be worth doing if it doesn't
affect current versions of OS x.