When using iostream.h, I get the same error twice.  On line 91, it says
there is a parse error before '__extension__'.  This same problem
occurs on line 208 of the same file.  Here's a piece of the
iostream.h code, starting at line 90:

#if defined(__GNUC__)
   __extension__ ostream& operator<<(long long n)
   ...
#endif

Line 208 is basically the same thing.  Maybe this is a problem with
the preprocessor commands?

This is almost certainly a result of using an old preprocessor and/or
C++ compiler with new (v2.8 or later) C++ headers.

I'm closing this report, as it isn't a DJGPP bug anyway.