Could not compile ferret under Arch Linux

I tried to compile ferret from source under Arch Linux. I have `wxgtk 2.8.12.1.-4` and `wxpdfdoc 0.9.3`.

Because of using wxgtk in version 2.8 (not 2.9 which isn't in Arch packages manager) I had to modified `Makefile`.

If I compiled ferret with command `rake build` a got this errors: 

    mainferret.cpp: In function ‘bool isHelpOption(wxString)’:
    mainferret.cpp:10:51: error: conversion from ‘const char [3]’ to ‘wxString’ is ambiguous
    mainferret.cpp:10:51: note: candidates are:

So I googled a little bit and I found, that strings wrapped in wxT() macro-function. When I did this, I succeeded.