[PATCH] Fix a stack overflow in pinbox allocator

[PATCH] Fix a stack overflow in pinbox allocator

MariaDB supports a "wait-free concurrent allocator based on pinning addresses".
In `lf_pinbox_real_free()` it tries to sort the pinned addresses for better
performance to use binary search during "real free". `alloca()` was used to
allocate stack memory and copy addresses.

To prevent a stack overflow when allocating the stack memory the function checks
if there's enough stack space. However, the available stack size was calculated
inaccurately which eventually caused database crash due to stack overflow.

The crash was seen on MariaDB 10.6.11 but the same code defect exists on all
MariaDB versions.

A similar issue happened previously and the fix in fc2c1e43 was to add a
`ALLOCA_SAFETY_MARGIN` which is 8192 bytes. However, that safety margin is not
enough during high connection workloads.

MySQL also had a similar issue and the fix
https://github.com/mysql/mysql-server/commit/b086fda was to remove the use of
`alloca` and replace qsort approach by a linear scan through all pointers (pins)
owned by each thread.

This commit is mostly the same as it is the only way to solve this issue as:
1. Frame sizes in different architecture can be different.
2. Number of active (non-null) pinned addresses varies, so the frame
   size for the recursive sorting function `msort_with_tmp` is also hard
   to predict.
3. Allocating big memory blocks in stack doesn't seem to be a very good
   practice.

For further details see the mentioned commit in MySQL and the inline comments.

All new code of the whole pull request, including one or several files
that are either new files or modified ones, are contributed under the
BSD-new license. I am contributing on behalf of my employer Amazon Web
Services, Inc.

Gbp-Pq: Name 2541-fix-stack-overflow-in-pinbox-allocator.patch