editors/emacs-devel: Update to 87e7390 and add NATIVECOMP option

Native Compilation adds support for compiling EmacsLisp to native code using
libgccjit. For more information see https://www.emacswiki.org/emacs/GccEmacs.

The option is off by default until it receives wider testing.

Co-authored-by: Ashish SHUKLA <ashish@FreeBSD.org>
Co-authored-by: Joseph Mingrone <jrm@FreeBSD.org>