Minor specification fixes

[jopperm]

• [x] Consider adding a __static_assert intrinsic (mainly to express constraints on the elaborated value of implementation parameters)
• [x] Allow alias-to-alias, combo-assignments (int & myalias = REG[1][63:32];)
• [x] Prohibit non-const alias to const entity
• [x] Fix order of alias grammar rule

[jopperm]

Diff

[AtomCrafty]

Regarding sizeof: There is an extra closing parenthesis in the definition ⌈bitsizeof(T)/8⌉). Personally, I find the ceiling brackets to be pretty difficult to see, so I would suggest replacing the definition by ceil(bitsizeof(T)/8) or (bitsizeof(T) + 7) / 8.

Both sizeof and bitsizeof also accept arbitrary expressions, returning the size of the expression's analyzed type.

[jopperm]

Thanks, fixed.