+(defvar *lambda-conversions*)
+
+(defvar *stack-allocate-dynamic-extent* t
+ "If true (the default), the compiler respects DYNAMIC-EXTENT declarations
+and stack allocates otherwise inaccessible parts of the object whenever
+possible. Potentially long (over one page in size) vectors are, however, not
+stack allocated except in zero SAFETY code, as such a vector could overflow
+the stack without triggering overflow protection.")