[PATCH] Add startswith function and use it instead of CONST_STRNEQ.

[Martin Liška]

> Given this has been broken for a little while, and given Alan's patch fixes the problem for arm/aarch64 sims (from what I tested), can we push this for now and get it addressed in some other way later, if someone wants it?
> 
> I think someone's hit this on riscv as well.

It's fixed now with Alan's patch:

commit 57ae980e3290c0c1a9fb4a93144cc5b24457f05a
Author: Alan Modra <amodra@gmail.com>
Date:   Wed Mar 31 10:02:08 2021 +1030

     Include string.h in bfd.h and delete LITMEMCPY, LITSTRCPY
     
     This fixes the issue that startswith depends on strncpy being
     declared, and not all projects using bfd.h include string.h before
     bfd.h.  I've also deleted some macros that don't find much use
     anywhere.
     
     bfd/
             * bfd-in.h: Include string.h.
             (LITMEMCPY, LITSTRCPY): Delete.
             * bfd-in2.h: Regenerate.
     binutils/
             * prdbg.c (pr_function_type): Replace LITSTTCPY with strcpy.

Cheers,
Martin