Development versions of cmocka require the intmax_t and uintmax_t types
to be defined by the time the test code includes the <cmocka.h> header.
These types are defined in the <stdint.h> header, which is included by
the <inttypes.h> header, which in turn is already explicitly included by
some of the programs in the tests/ directory. Ensure all programs in
that directory that include the <cmocka.h> header also include the
<inttypes.h> header to future-proof the code while keeping the change
set minimal and the resulting code consistent. Also prevent explicitly
including the <stdint.h> header in those programs as it is included by
the <inttypes.h> header.
Remove the `isc_threadarg_t` and `isc_threadresult_t`
typedefs which were unhelpful disguises for `void *`,
and free the dummy jemalloc allocation sooner.
The spinlock is small (atomic_uint_fast32_t at most), lightweight
synchronization primitive and should only be used for short-lived and
most of the time a isc_mutex should be used.
Add a isc_spinlock unit which is either (most of the time) a think
wrapper around pthread_spin API or an efficient shim implementation of
the simple spinlock.
