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

[noloader at gmail dot com]

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

--- Comment #4 from Jeffrey Walton <noloader at gmail dot com> ---
(In reply to Jonathan Wakely from comment #3)
> Jeffrey, could you please add the output of '/opt/local/bin/g++-mp-5
> -dumpmachine' to the Target field of this bug report? Thanks.

  $ /opt/local/bin/g++-mp-5 -dumpmachine
  ppc-apple-darwin9

If it matters, the machine is 32-bit by default:

  $ getconf LONG_BIT
  32

But its capable of 64-bit code with -m64 or -arch ppc64.