1543
   let's review this patch history again.  with longer output context.
   and the knowledge that static memory is zero-initialised whether you
   want this or not.
   1550
   let's review this patch history again.
   1553
   so the default context reuse is right at the top of the function.  if
   there is one, it bumps the refcount, points and returns, everything's
   good
   libusb_init locks around a global lock, so things in it are not
   simultaneous.
   the check if (ctx || !usbi_default_context) ... I think this is saying
   to only execute the block if a new context is being made?  but isn't
   that always true?  it replaced if (!ctx) which says, only if this is
   the default context.
   let's see if the block is always true.
   if ctx is nonzero, that's the normal case.  then edge cases would be
   ctx is zero.
   if ctx is zero, then there's a block that checks for
   usbi_default_context being nonzero, and short-circuits, returning.
   so, after that block, usbi_default_context is zero if ctx is zero.
   therefore, ctx || !usbi_default_context ....
   uhh is saying ctx || (!ctx && !usbi_default_context)
   and we just said that those two being zero, one implies the other
   so ctx || !ctx, it would always be true.
   hard to verify.  4 cases, 4 combinations of nonzeroness.
   1 is eliminated by the short-circuit: !ctx, +dflt
   leaves 3: ctx, dflt; ctx, !dflt; !ctx, !dflt
   1601
   1603
   boolean logic! woot!  oh man my whole universe is partial truth tables
   right now
   omigod trues and falses, everywhere
   I just so badly want to question whether true is _really_ true, or
   false _really_ false.  could a 1 or a 0 be a trick?  you never know!
   !ctx, dflt <- eliminated by short circuit?
   remaining? -> ctx, dflt; ctx, !dflt; !ctx, !dflt
   1606
   suddenly taking a break