Genie:  Neg-check compute_rowBytes_from_bounds()

Check for a width exceeding 32767 (which is REALLY big, and should never
happen, and can only happen if bounds.left is negative), and return zero
in that case.

Also, silence a clang operator precedence warning.
Nitrogen iteration:  Store AEDescList in iterator

Store a copy of the AEDescList in AEDescList_ItemData_ValueIterator, not
just a reference.  This silences a warning about the default constructor
(which was clearly wrong).  As for whether it makes the intended use any
safer, it removes the possibility of referencing the AEDescList after it
ceases to exist, but if the calling code calls AEDisposeDesc() (and sets
the dataHandle to NULL) on the original, then the iterator will possibly
crash calling AEGetNthPtr() on its stale copy, instead of getting a mere
error.  In any event, correct usage doesn't change, and this patch fixes
the default case.
A-line:  Initialize references with non-temp data
v68k:  Use the byte_count() "macro" function
v68k:  Silence clang operator precedence warnings
d68k:  Silence clang operator precedence warnings
relix:  Silence clang operator precedence warning
Genie:  Silence clang operator precedence warning
Merge branch 'parens-for-clang'