It recommends using SQLITE_USE_ALLOCA on systems that support it. On
macOS and FreeBSD, the man page for alloca says something like this:
The alloca() function is machine and compiler dependent; its use is
The alloca() function is slightly unsafe because it cannot ensure that
the pointer returned points to a valid and usable block of memory. The
allocation made may exceed the bounds of the stack, or even go further
into other objects in memory, and alloca() cannot determine such an
error. Avoid alloca() with large unbounded allocations.
FreeBSD 12.0-RELEASE-p9 September 5, 2006 FreeBSD 12.0-RELEASE-p9
Not a big deal, just a little confusing for alloca() to be recommended
yet discouraged by OS.