changes in sbcl-2.3.5 relative to sbcl-2.3.4:
* enhancement: Unicode support has been updated to support version 15.0.0 of
the Unicode standard, including addition of characters and their collation
keys, and refinements to grapheme-, word- and line-breaking algorithms.
* new contrib module: an interface to perf, a performance-analysing tool for
Linux. (thanks to Luke Gorrie and Philipp Marek)
* platform support:
** on x86-64, prefer using the LEAVE instruction rather than MOV/POP at
function epilogue to restore RSP/RBP.
** support SB-FUTEX on OpenBSD. (thanks to Elijah Stone)
** support SB-FUTEX on Darwin/arm64. (thanks to Elijah Stone)
** fix compilation with clang on Windows. (lp#2018601, thanks to Andrew)
* bug fix: inspecting objects with unbound slots produces output that is less
confusable with the string "unbound". (thanks to Nicolas Martyanoff)
* optimization: make TN-REFs doubly-linked, allowing faster deletion.
(lp#2018124, reported by Matt Kaufmann)
* optimization: MAPCAN/MAPCON are less accidentally quadratic. (thanks to
Gleefre)
* optimization: improved arithmetic operations in the form of
(the word-sized-type (-+* word-sized word-sized)) when the result can
overflow. For arm64 and x86-64.