RFC: Adding VxWorks PIC support to various backends

[Ian Lance Taylor]

Richard Sandiford <richard@codesourcery.com> writes:

>   1) Wrap it in #ifdef TARGET_VXWORKS_RTP.
> 
>   2) Provide an always-false definition of TARGET_VXWORKS_RTP in
>      arm.h, i386.h, etc.  Also provide dummy definitions of the
>      VXWORKS_GOTT_* macros.
> 
>   3) Provide an always-false definition of TARGET_VXWORKS_RTP in
>      defaults.h.  Also provide dummy definitions of the VXWORKS_GOTT_*
>      macros.
> 
>   4) Like (3), but provide the real VxWorks default values of the
>      VXWORKS_GOTT_* macros (rather than dummy ones).

Provide an always-false definition of TARGET_VXWORKS_RTP in arm.h,
i386.h, etc.  Define the other macros in config/vxworks.h.  Add
vxworks.h to config.gcc for the appropriate targets.

(I assume here that you otherwise only need to change the files in
config/i386, config/arm, etc.)

Ian