[PATCH] Replace usage of ar with stored library manifest files

[Mark Wielaard]

Hi Michael,

On Mon, 2025-01-13 at 23:56 +0000, Michael Pratt wrote:
> The ar program is called to assemble a list of objects
> within each archive to assist in building combined libraries,
> however make already has this information
> when processing the subdirectory for that respective library.
> The list can be saved in a "manifest" file
> instead of being generated whenever it is needed
> for use with other subdirectories.
> 
> Even though the difference in time is insignificant,
> a simple "echo" and "cat" is as much as 10 times faster
> than a call to "ar t" for printing the archive members.
> 
> Since elfutils builds ar,
> this also removes the awkward circular dependency
> where an installation of ar is required
> to build the libraries for ar.
> 
> Additionally, not every version of ar is equally portable,
> as native versions of ar on macOS and other BSD-like distributions
> may print out a special archive member like "__.SYMDEF"
> which is not a compiled object but rather just metadata
> from ranlib, leading to a build failure.
> 
> Avoid these limitations by removing usage of ar
> and adding build and clean rules
> for the usage of archive manifest files.

Even though I wasn't even aware of these limitations (I don't think
anybody ever reported running into them), I really like this change.
And the implementation is also very clean.

>     * .gitignore: exclude ".manifest" file extension.
>     * backends/Makefile.am: add manifest file build and clean rules.
>     * debuginfod/Makefile.am: Likewise.
>     * lib/Makefile.am: Likewise.
>     * libasm/Makefile.am: Likewise.
>     * libcpu/Makefile.am: Likewise.
>     * libdw/Makefile.am: Likewise,
>       and set object lists to manifest contents.
>     * libdwelf/Makefile.am: Likewise.
>     * libdwfl/Makefile.am: Likewise.
>     * libebl/Makefile.am: Likewise.
>     * libelf/Makefile.am: Likewise,
>       and set object lists to manifest contents.
>     * src/Makefile.am: Likewise.

Pushed as is.

Thanks,

Mark