bug#48804: 27.2; compilation emacs on macOS

[Eli Zaretskii]

> Date: Thu, 3 Jun 2021 22:34:44 +0100
> From: Alan Third <alan@idiocy.org>
> Cc: nisoni@algon.dk, 48804@debbugs.gnu.org
> 
> > in addition to libgccjit, you need to install gcc-11, and to insert 
> > somethin like the following into your .bash_profile
> > 
> > export CC="/usr/local/Cellar/gcc/11.1.0/bin/gcc-11”
> > 
> > (assuming you use homebrew to install additional unix tools).
> 
> FYI GCC is unable to build GUI emacs on macOS (or at least the native
> GUI). And there's no requirement to build Emacs with GCC for native
> compilation to work, as long as libgccjit was installed with Homebrew,
> Emacs configure should be able to find it.

That is true, but AFAIK libgccjit invokes gcc as part of the native
compilation, so GCC does need to be installed, even if Emacs is built
with another compiler.

(And maybe we should ping the GCC developers to finish the work on the
features needed to build Emacs -- there's a Bugzilla PR, where, last
time I checked, there was some work being done).