Pull htab_eq_string from gcc libiberty

[Simon Marchi]

On 2021-05-07 10:33 a.m., Richard Earnshaw via Gdb-patches wrote:
> NP, I'm one of the few who still do shared tree builds and to do that you need the copies of libiberty and include from binutils/gdb (well, it's mostly the extended headers).
> 
> It does make me wonder why, in the days of git, we aren't using git modules in both tools now for libiberty and include, then we wouldn't have sync problems.

Every time git (sub-?)modules are mentioned, it attracts a lot of hate,
for some reason.  But I think it would apply really well here, so I
would be in favor of that.

Simon