work around ambiguity with msvc and old gcc

C:/cygwin/home/tinderbox/master-build/l10ntools/source/po.cxx(188) : error C2666: 'std::fpos<_Statetype>::operator !=' : 2 overloads have similar conversions
        with
        [
            _Statetype=_Mbstatet
        ]
        C:/PROGRA~2/MICROS~1.0/VC/include\iosfwd(116): could be 'bool std::fpos<_Statetype>::operator !=(const std::fpos<_Statetype> &) const'
        with
        [
            _Statetype=_Mbstatet
        ]
        or       'built-in C++ operator!=(std::streamoff, long)'
        while trying to match the argument list '(std::fpos<_Statetype>, long)'
        with
        [
            _Statetype=_Mbstatet
        ]

Change-Id: Id1375d68996414c5ccf75d5d3ebc0afad061e3d2

l10ntools/source/po.cxx

@@ -185,7 +185,7 @@ void GenPoEntry::setFuzzy(const bool bFuzzy)
 //Write to file
 void GenPoEntry::writeToFile(std::ofstream& rOFStream) const
 {
-    if ( rOFStream.tellp() != 0 )
+    if ( rOFStream.tellp() != std::ofstream::pos_type( 0 ))
         rOFStream << std::endl;
     if ( !m_sExtractCom.isEmpty() )
         rOFStream