rtemself.h: Updated to keep in sync with config/i386/linux.h.
* config/i386/rtemself.h: Updated to keep in sync with
config/i386/linux.h.
* configure.in: Added sh-rtemself.
* configure: Rebuilt.
* config/sh/rtems.h: Removed -D__ELF__ since it is now COFF.
* config/sh/rtemself.h: New file.
* config/rs6000/rtems.h: Defined STARTFILE_DEFAULT_SPEC.