Why is GCL built with gcc@4.9?

[Mark H Weaver <mhw@netris.org>]

Hi Efraim,

I'm curious about this commit of yours from April 2017:

--8<---------------cut here---------------start------------->8---
commit 5c7815f205e9164d4b82378de91bee7a65bcfbcb
Author: Efraim Flashner <efraim@flashner.co.il>
Date:   Mon Apr 10 05:20:09 2017 +0300

    gnu: gcl: Build with gcc@4.9.
    
    * gnu/packages/lisp.scm (gcl)[native-inputs]: Add gcc@4.9.
--8<---------------cut here---------------end--------------->8---

Do you remember why you did this?  There's no explanation in the
comments, nor in the commit log, nor in the 'bug-guix' or 'guix-devel'
email archives from around that time.

I'd like to remove it, and I've verified that on x86_64-linux, GCL
builds successfully with the default compiler.

In general, it would be good to include comments with rationale for
workarounds like this, so that we have some idea of when the workaround
can be removed, and what tests we must do to ensure that the original
problem has been addressed.

     Thanks,
       Mark