bug#64830: 30.0.50 C++ treesitter mode no coloration

[Eli Zaretskii <eliz@gnu.org>]

> Date: Mon, 26 Aug 2024 17:25:34 +0000
> Cc: Eli Zaretskii <eliz@gnu.org>, 64830@debbugs.gnu.org
> From: Alan Mackenzie <acm@muc.de>
> 
> Ah, that's it!  I didn't know the grammar library in use was the one in
> ~/.emacs/tree-sitter.  There, I've got 
> 
>     -rwxr-xr-x 1 acm acm 2319888 Jan 19  2023 libtree-sitter-cpp.so
> 
> , which is very old.  In my /usr/lib64, I've got
> 
>     lrwxrwxrwx 1 root root      26 Aug  4 18:13 /usr/lib64/libtree-sitter-cpp.so.0 -> libtree-sitter-cpp.so.0.14
>     lrwxrwxrwx 1 root root      23 Aug  4 18:13 /usr/lib64/libtree-sitter-cpp.so -> libtree-sitter-cpp.so.0
>     -rwxr-xr-x 1 root root 3175712 Aug  4 18:13 /usr/lib64/libtree-sitter-cpp.so.0.14
> 
> Why do we have this extra complication with ~/.emacs.d/tree-sitter as a
> location for libraries?  In GNU/Linux distributions (well, in Gentoo at
> any rate), newly downloaded libraries are put into /usr/lib64, so that
> anybody naively updating a grammar library is going to have it masked out
> by the old one still in ~/.emacs.d/tree-sitter.  Maybe I don't understand
> the library mechanism as well as I ought to.

We support grammar libraries in ~/.emacs.d/tree-sitter so that users
could easily install versions of grammar libraries different from what
their sysadmins decide to install.