changes in sbcl-2.4.1 relative to sbcl-2.4.0:
* enhancement: compact instance headers are partially supported with the
mark-region parallel garbage collector.
* enhancement: functions with declared return types have their return values
type-checked in optimization regimes with high SAFETY and (DEBUG 3).
* platform support:
** disable ASLR on FreeBSD. (lp#2047655, thanks to Konstantin Belousov)
** link to libpthread on FreeBSD. (thanks to Konstantin Belousov)
** restore build on 64-bit riscv. (lp#2034713, lp#2048869, reported by
Guillaume LE VAILLANT)
** restore build on 64-bit ppc.
** fix case in referring to a header file. (lp#2047726, thanks to Andrew Kravchuk)
** the fastrem-32 feature (for optimized computations of FLOOR) is now
available on all platforms.
* bug fix: resweep moved lines after compaction in the mark-region parallel
garbage collector.
* bug fix: infinite loops in the compiler on some constructs with SATISFIES
types. (lp#2047289, lp#2047706, lp#2049631)
* optimization: various hash tables implementing part of the system
(packages, Unicode data tables) have been converted to use perfect hash
functions.
* optimization: TYPECASE on structure class hierarchies is implemented using
a perfect hash.
* optimization: eliminate bound checks with relative offsets. (lp#1830314)
* optimization: the compiler has more knowledge of how to optimize
DIGIT-CHAR.
* optimization: the compiler can elide intermediates for some calls to
APPLY, CONCATENATE and MAKE-ARRAY with arguments that are freshly-consed
modifications of existing sequences.
* optimization: (LOOP FOR X IN (REVERSE LIST) ...) is now faster and conses
less.
* optimization: (LOOP ... APPEND ...) is more compact, and does less work if
appending NIL.
* optimization: type tests of various array types are faster and shorter.