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.

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

The message read odd with the missing be

Allows us to avoid using source variables.

Allows us to avoid using source variables.

Continuation of commit 4e47b053c9d799.

All unittests still pass.

- We don't need the Threads target workaround anymore, that breaks the
build with Qt6 even.
- The Gradle wrapper shipped with Qt is no longer installed as executable,
so we need to run this in sh explicitly.
- Qt6 uses a different Android Gradle plugin version (not to be confused
with the Gradle version), which we need to make available for the
configure_file() call on the build.gradle file.

With this most Framework modules build against Qt6 here.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

SunOS and variants (Solaris, OpenSolaris, illumos, etc al.) do not need a separate library for inotify.