[MacPorts] #53226: PowerMac, GCC 5.4 and "error: 'std::log2' has not been declared"

[MacPorts]

#53226: PowerMac, GCC 5.4 and "error: 'std::log2' has not been declared"
-----------------------+------------------------------
  Reporter:  noloader  |      Owner:
      Type:  defect    |     Status:  new
  Priority:  Normal    |  Milestone:
 Component:  ports     |    Version:  2.3.5
Resolution:            |   Keywords:  c++11 cmath log2
      Port:  g++-mp-5  |
-----------------------+------------------------------

Comment (by noloader):

 I found I could work around the issue with the following. I'm not sure its
 a good workaround, though. I think I'm supposed to avoid adding symbols to
 std namespace like this.

 {{{
 namespace std
 {
    inline double log2(double d)
       {return ::log2(d);}
 }
 }}}

--
Ticket URL: <https://trac.macports.org/ticket/53226#comment:1>
MacPorts <https://www.macports.org/>
Ports system for macOS