[Fortran] Fix for multiple definitions of '_xml' function

This was causing linker errors when trying to link with the Fortran library.

src/fortran/fct.cpp

@@ -26,6 +26,8 @@ typedef Cabinet<Transport> TransportCabinet;
 
 typedef integer status_t;
 
+namespace {
+
 XML_Node* _xml(const integer* n)
 {
     return &XmlCabinet::item(*n);
@@ -51,6 +53,8 @@ Transport* _ftrans(const integer* n)
     return &TransportCabinet::item(*n);
 }
 
+} // unnamed namespace
+
 std::string f2string(const char* s, ftnlen n)
 {
     int k;

src/fortran/fctxml.cpp

@@ -23,11 +23,15 @@ template<> XmlCabinet* XmlCabinet::s_storage = 0;
 
 typedef integer status_t;
 
+namespace {
+
 XML_Node* _xml(const integer* i)
 {
     return &XmlCabinet::item(*i);
 }
 
+} // unnamed namespace
+
 std::string f2string(const char* s, ftnlen n);
 
 extern "C" {