[GOLD][PATCH][ARM] Better error reporting for the deprecated relocations

[Doug Kwan (關振德)]

This is okay to me.

在 2010年10月9日上午5:19，Viktor Kutuzov <vkutuzov@accesssoftek.com> 寫道：
> This patch provides a better error reporting for the deprecated and/or
> unsupported ARM relocations. Currently Gold reports an internal error on
> that kind of relocations.
>
> Such as
>
> ld-new: error: arm_bl_in_range.o: unsupported reloc 1 against global
> symbol _backward_target
>
> instead of
>
> ld-new: internal error in relocate, at ../../src/gold/arm.cc:9044
>
>
> -Viktor
>
>    * arm.cc (Target_arm::Scan::local): Report the unsupported reloc
>    error for the deprecated relocations.
>    (Target_arm::Scan::global): Likewise.
>    (Target_arm::Relocate::relocate): Likewise.
>