Change log:
* config/gthr.m4: Added rdos thread header.
* gcc/config/i386/i386.c: Provided a way to define a default setting for 
medium memory model and PIC. Provided a way to define a default value for 
large-data-threshold.
* gcc/config/i386/i386.h: Defined default value for medium memory model & 
PIC.
* gcc/config/i386/rdos.h: Added new file for rdos target definition.
* gcc/config.gcc: Added rdos target

The change to gthr.m4 requires rebuilding the configure scripts.

Tested with target rdos and rdos32. Is this ok for trunk?

Regards,
Leif Ekblad