changes in sbcl-1.5.8 relative to sbcl-1.5.7:
* platform support:
** support for Mac OS X Catalina
** improvements in interoperability with C code compiled with memory
sanitization options
** libsbcl.so links to zlib when sb-core-compression is enabled.
(lp#1845763, thanks to Juan M. Bello-Rivas)
** workarounds for BSD issues around mmap() and pthread_attr_setstack().
(lp#1845936)
** support SSE for bzero if available on OpenBSD
* optimizations:
** improved type understanding and translations for division operators
(including TRUNCATE, GCD, LCM).
** sequential comparisons and branches can elide intermediate comparisons.
(lp#1847284)
** convert EQUAL and EQUALP to EQL if either of the arguments is a type
for which the structural equality predicate is identical to the simpler
equality check. (lp#1848583)
** internal operators implementing string comparisons produce
simpler-to-consume values. (lp#1848776)
* bug fix: inspecting adjustable arrays and vectors with fill pointers works
better. (lp#1846191, reported by Yves Pagani)