changes in sbcl-2.6.1 relative to sbcl-2.6.0:
  * minor incompatible change: the never-documented :NO-CONSTRUCTOR-DEFUN
    option to DEFSTRUCT is no longer supported.
  * platform support:
    ** support for the LoongArch architecture has been added.  (thanks to
       ZiLong Wang)
    ** support for FreeBSD on 32-bit and 64-bit PowerPC platforms has been
       added.  (thanks to Piotr Kubaj)
    ** SB-ALIEN now supports passing and returning structures by value (rather
       than by reference) in accordance with the platform ABIs, on x86-64 and
       arm64 platforms.  (lp#313202, thanks to Jesse Bouwman)
    ** wide compare-and-exchange is supported on the arm64 platform for
       Armv8.1-A or later.
  * bug fix: signal a DIVISION-BY-ZERO error in calls of (/ 0 0).
    (lp#2137266, reported by khbit)
  * bug fix: compiler infinite loop from previously-acceptable recursive
    inline expansions.  (lp#2137380, reported by Frode Fjeld)
  * bug fix: unnormalized inequality constraints causing a compiler infinite
    loop.  (lp#2137422, reported by Jesse Bouwman)
  * bug fix: compiler infinite loop from a deleted loop with an remnant
    TAGBODY.  (lp#2137493)
  * bug fix: miscompilation of REDUCE #'APPEND with non-null INITIAL-VALUE and
    :FROM-END NIL.  (lp#2137736, reported by Vasily Postnicov)
  * bug fix: encode XREF locations in a way that allows for higher form
    numbers.  (lp#2137765, reported by Jim White)
  * bug fix: lookups of optimized memory movers fails when *PRINT-BASE* is not
    10.  (lp#2138812, reported by Robert Dodier)
  * bug fix: CLRHASH on a hash table with weak keys should not corrupt the
    table's index vector.  (lp#2138965, reported by Patrick Poitras)
  * bug fix: address a number of type derivation subtleties related to
    floating point zeros.
  * optimization: various combinations of arithmetic operations with variables
    and constants are simplified to have fewer calls.
  * optimization: elide full calls to CONJUGATE when its argument is known to
    be of type REAL.  (lp#2137354, thanks to Vasily Postnicov)
  * optimization: the compiler knows more about the type and results of
    ARRAY-DIMENSION.
  * optimization: transform ARRAY-DIMENSIONS away on objects with array types
    of known dimensions.  (lp#2138581, thanks to Vasily Postnicov)
  * optimization: (equal (array-dimensions a) (array-dimensions b)) does not
    cons intermediate lists.
  * optimization: (make-array (array-dimensions a)) does not cons a list.