codegen errors: type checks are inserted as necessary. (lp#1177703)
* bug fix: Unsigned modular arithmetic is correctly converted into signed
modular arithemtic (mostly to exploit fixnum-width VOPs). (lp#1026634)
+ * bug fix: a combination of inlined local function with &optional and
+ recursion no longer causes undescriptive compiler errors. (lp#1180992)
* optimization: faster ISQRT on fixnums and small bignums
* optimization: faster and smaller INTEGER-LENGTH on fixnums on x86-64.
* optimization: On x86-64, the number of multi-byte NOP instructions used