-The eventual plan is for SBCL to bootstrap itself in two phases. In
-the first phase, the cross-compilation host is any old ANSI Common
-Lisp (not necessarily SBCL) and the cross-compiler won't handle some
-optimizations because the code it uses to implement them is not
-portable. In the second phase, the cross-compilation host will be
-required to be a compatible version of SBCL, and the cross-compiler
-will take advantage of that to implement all optimizations. The
-current version of SBCL only knows how to do the first of those two
-phases, with a fully-portable cross-compiler, so some optimizations
-are not done. Probably the most important consequence of this is that
-because the fully-portable cross-compiler isn't very smart about
-dealing with immediate values which are of specialized array type
-(e.g. (SIMPLE-ARRAY (UNSIGNED-BYTE 4) 1)) the system sometimes has to
-use unnecessarily-general array types internally.
-