mingw: stop using nedmalloc

[dscho]

Git for Windows' SDK wants to update GCC to v16. Since it is used in the CI builds also of the git/git repository, it is crucial that GCC can compile even the latter all right, but currently it does not, see https://github.com/git-for-windows/git-sdk-64/actions/runs/25244795074.

Git for Windows switched away from nedmalloc to mimalloc a long time ago, anyway. I plan on upstreaming this soon-ish, after this here patch lands.

Note that with this patch, I reverse the order I indicated in https://lore.kernel.org/git/00fd3145-b3d2-ddab-466d-d06fd27298ec@gmx.de/: I first disable nedmalloc for MINGW builds (and possibly drop the vendored-in nedmalloc from Git's source code). The reason is that I am still trying to figure out the best way to integrate mimalloc: git-for-windows@d67535b61dd (Import the source code of mimalloc v2.2.7, 2026-01-16) in patch form would weigh some ~700kB, which would not only be rejected by the Git mailing list, but which I myself would reject if I was the Git maintainer merely on the basis of the sheer size of the patch. Probably the best course of action is to add support for a non-vendored-in mimalloc first, then keep the vendored-in copy in Git for Windows (where no mailing list stands in the way of large patches). Whatever it will be, it's best to fast-track this here patch to disable nedmalloc for Windows builds, so that the CI builds can switch to using GCC 16 (and the current Git for Windows SDK) on Windows.

cc: Patrick Steinhardt ps@pks.im

[dscho]

/submit

[gitgitgadget]

Submitted as pull.2104.git.1777811392756.gitgitgadget@gmail.com

To fetch this version into FETCH_HEAD:

git fetch https://github.com/gitgitgadget/git/ pr-2104/dscho/stop-using-nedmalloc-with-mingw-v1

To fetch this version to local tag pr-2104/dscho/stop-using-nedmalloc-with-mingw-v1:

git fetch --no-tags https://github.com/gitgitgadget/git/ tag pr-2104/dscho/stop-using-nedmalloc-with-mingw-v1

[gitgitgadget]

Patrick Steinhardt wrote on the Git mailing list (how to reply to this email):

On Sun, May 03, 2026 at 12:29:52PM +0000, Johannes Schindelin via GitGitGadget wrote:
> From: Johannes Schindelin <johannes.schindelin@gmx.de>
> Rather than patch the unmaintained vendored sources to silence the
> warning, stop opting into nedmalloc altogether on MINGW. The platform
> allocator is what every non-MINGW build already uses, and a fresh
> build of git.git's master against a minimal Git for Windows SDK
> upgraded to GCC 16, with `USE_NED_ALLOCATOR` removed from the MINGW
> section, completes successfully.
> 
> The compat/nedmalloc/ subtree itself is left in place to keep this
> change minimal; nothing in the build links against it any longer, so
> it can be removed in a follow-up if desired.

I guess this is fair as an intermediate step. But seeing that this
removes the last user per our "config.mak.uname" I do wonder whether we
want to maybe drop nedmalloc completely. Not necessarily in this patch,
but maybe in a subsequent step?

Thanks!

Patrick

[gitgitgadget]

User Patrick Steinhardt <ps@pks.im> has been added to the cc: list.