[PATCH Gold] Recognize clang-style crtbegin and crtend files

[Cary Coutant]

> Clang uses two forms of its own (plus all of the gcc ones), which can
> be found in clang/lib/Driver/ToolChain.cpp:416:
>
> $(target_directory)/clang_rt.crtbegin.o
> clang_rt.crtbegin-$target.o
>
> This updated patch supports both of those forms.

Thanks. This is OK.

-cary