bug#60102: Move gv-expander of substring to cl-lib

[Stefan Monnier]

Tags: patch

Tags: patch

The `gv-expander` of `substring` uses the `cl--set-substring` function
that's defined only in `cl-lib`, so currently, you can compile

    (setf (substring ...) ...)

without requiring `cl-lib` but at run time it will tend to signal
a `void-function` error.
We could autoload `cl--set-substring`, but I think a better choice is to
move this `gv-expander` to `cl-lib.el`.

There are 2 other place definitions in `gv.el` which similarly rely on
helper functions defined in `cl-lib` (namely `buffer-substring` and
`frame-visible-p`) which we could move as well, but since we marked
those as obsolete anyway I think we can "let them die" where they are,
with their quirks left alone.  If you feel otherwise, I can update the
patch to move them to `cl-lib.el` as well.


        Stefan


 In GNU Emacs 30.0.50 (build 1, x86_64-pc-linux-gnux32, GTK+ Version
 3.24.35, cairo version 1.16.0) of 2022-12-09 built on alfajor
Repository revision: b134e7e6abf18286d38e1b589f0fdae523cf1e73
Repository branch: work
Windowing system distributor 'The X.Org Foundation', version 11.0.12101003
System Description: Debian GNU/Linux bookworm/sid

Configured using:
 'configure -C --enable-checking --enable-check-lisp-object-type --with-modules 
--with-cairo --with-tiff=ifavailable
 'CFLAGS=-Wall -g3 -Og -Wno-pointer-sign'
 PKG_CONFIG_PATH=/home/monnier/lib/pkgconfig'

gv-substring.patch
Description: Text Data