using C++ STL containers in GCC/gfortran source code

[Janus Weil]

To get to more specific questions ...

> Basically the only STL construct used in the Fortran FE right now
> seems to be std::swap, and a single instance of std::map in
> trans-common.c.

I see that fortran/trans-common.c has:

#define INCLUDE_MAP

and apparently there is also a INCLUDE_STRING macro. I guess if I want
to use std::string I don't #include <string>, but #define
INCLUDE_STRING, right? Why are those macros needed, exactly?

Cheers,
Janus