gold input section handling

[David Miller]

From: Ian Lance Taylor <iant@google.com>
Date: Mon, 14 Apr 2008 21:08:39 -0700

> I saw your later post, but this seems like a reasonable argument to
> me.  I changed gold so that it ignores SHF_WRITE and SHF_EXECINSTR
> when merging sections.  It still pays attention to SHF_ALLOC, except
> for sections with zero flags.
> 
> I committed the attached patch.

I regression tested this with my sparc target, no regressions.

I also made sure that this can mostly build a sparc64 Linux kernel
using unmodified sources.

Thanks!