RFC: Bump minimum GNU Make version to 3.81

[Jonathan Wakely]

On Thu, 25 Jun 2026, 08:14 Richard Biener, <richard.guenther@gmail.com>
wrote:

> On Wed, Jun 24, 2026 at 6:53 PM Jonathan Wakely via Gcc <gcc@gcc.gnu.org>
> wrote:
> >
> > Currently we document that GNU Make 3.80 is required. That was
> > released in 2002. GNU Make 3.81 was released in April 2006. I would
> > like to suggest that 20 years is enough time for 3.81 to be
> > widespread.
> >
> > Bumping the requirement to 3.81 would allow us to use the $(abspath
> > ...) function, which we already started using in libstdc++, not
> > realising that it relies on a newer version than our docs require.
>
> OK, can you produce a patch to install.texi?  Can you check whether
> branches are affected by the effective bump in requirement and backport
> as well?
>


Alexandre (and Jakub) already patched the affected branches to stop using
abspath, so I think we could just change the prerequisite for trunk and not
the release branches.