Proper Place for builtin_define(__ELF__)

[Joel Sherrill]

Hi

We are in the process of porting RTEMS to the Microblaze and gcc does
not have __ELF__ as a predefine. In looking around at where to add it,
it looks like there are multiple ways to do it. We see variations on
the following patterns:

+ dbxelf.h
+ OS specific header in config/
+ Arch/OS specific header

Integrating dbxelf.h into the microblaze seems risky for one simple
builtin_define(). Adding it to config/microblaze/rtems.h won't address
the microblaze-elf target.

A suggestion on where to add the builtin_predefine is appreciated.

Thanks

--joel