changes in sbcl-2.1.2 relative to sbcl-2.1.1:
* platform support:
** support for ARM64 macOS;
** improvement in coverage mark implementation on non-x86oid backends,
approaching the existing x86oid support;
** more empirically-robust retrieval of the program counter from illegal
instruction traps on SPARC;
** retain fewer dead objects when saving cores with precise collectors.
* incompatible change: MAP-ALL-SAMPLES and MAP-TRACE-SAMPLES
are no longer present in the SB-SPROF contrib module.
* minor incompatible change: SB-SPROF:WITH-PROFILING defaults to all
threads. SB-SPROF:START-PROFILING no longer accepts a :SAMPLING keyword.
* enhancement: the sb-introspect contrib now supports finding the lambda
lists of method combinations. (thanks to Didier Verna)
* enhancement: short-form DEFSETF now stores a source-location.
* bug fix: canonical unions of CONS types were being incorrectly computed.
(lp#1912863, reported by James Kalenius)
* bug fix: better understanding of array simplicity (or otherwise) in the
type system. (lp#1903241)
* bug fix: unions of rational and integer types now have a single canonical
form, allowing more correct reasoning about them in the type system.
* bug fix: less likely to overclaim certainty about type equality of union
types. (lp#1916040)
* bug fix: HANDLER-BIND evaluates the forms producing handler functions only
once. (lp#1916302, reported by Christophe Junke)
* optimization: FIND on constant sequences can be compiled into a jump
table, in a similar manner to POSITION
* optimization: the compiler's awareness of numeric contagion rules for
operations on pairs of floating point numbers is improved. (lp#1914094,
thanks to Andrew Berkley)