std::auto_ptr is being removed when building with newer C++ standards.
Our consumers so far work around that by reducing the C++ standard for
files or targets using exiv2. That however no longer works with Qt 6,
which insists on C++17 at least.

Instead, we now make std::auto_ptr visible again in libc++ for exiv2
users.

This should fix the FreeBSD Qt 6 build of KFileMetaData.

In KF 5.90 we already looking for 5.15.2
and looking something lower than that
is a bit meaningless

By now everyone should have it

Warning that it is unstable is just producing noise

If someone really doesn't have it available the caller must not request it

This reverts commit 178c4dfbf4eb5ad7c5aef4838f190f717f97766f.

Instead of creating an MR, I forgot I was on master...

GIT_SILENT

For example, if you have:
//This is a comment

now clang-format won't change it to:
// This is a comment

We're mainly interested in formatting the code, not the comments, so that
cuts down on some noise when running clang-format.

CCBUG: 456819

Only install pre-commit hooks if KDE_CONFIGURE_GIT_PRE_COMMIT_HOOK
is called frm CMAKE_CURRENT_PROEJECT, eg. don't install pre-commit
hooks if ECM is inside a submodule or fetched-content.