sa_assert: assert-like macro, enabled only for use with static analyzers
Among some here, there is a strong aversion to the use of "assert", yet
some others think it is essential (when applied judiciously) even --
perhaps "especially" -- at the heart of libraries and core hypervisor-
related code.
Here is a compromise that lets us make assertions about the code (e.g.,
to tell static analyzers about invariants) without even a hint of risk
of an abort.
* src/internal.h [STATIC_ANALYSIS]: Include <assert.h>.
(sa_assert): Define. A no-op most of the time, but equivalent
to classical assert when STATIC_ANALYSIS is nonzero.