changes in sbcl-2.4.8 relative to sbcl-2.4.7: * bug fix: the elftool utility finds a writeable directory in more situations. (thanks to Shinmera) * bug fix: SLOT-MAKUNBOUND does not attempt to dereference a PROGN variable in the interpreter. * bug fix: READ-SEQUENCE into displaced arrays with a non-zero offset now writes to the right memory location. * bug fix: fix some erroneous file position calculations in the editcore utility (exposed by a change in the libzstd compression implementation). * bug fix: do not break the build on STYLE-WARNINGs for earlier SBCL build hosts. (lp#2064671, reported by Patrick Poitras) * bug fix: various bug fixes for ppc64le (lp#2074275, reported by Claude R. C.) * bug fix: address a rounding error in the TAN type deriver which led to a miscompile in cl-pdf. (lp#2077100, reported by Gian Pierro Carrubba) * bug fix: overoptimization of FIND with a :TEST of CHAR-EQUAL. (lp#2077539) * optimization: detection of duplicate names in loaded code now scales subquadratically. * optimization: switch from Floyd's to Brent's cycle detection for lists. * optimization: EQUAL on lists should be faster. * optimization: fewer filesystem operations are performed when working out what to LOAD. * optimization: various microoptimizations on hash tables and associated operations. * optimization: strings are now hashed using FNV-1A, replacing Bob Jenkins' one-at-a-time hash. * optimization: fewer redundant validations of the sequence bounding indices in POSITION on strings. * optimization: many improvements to type derivation on the arguments to and results of standard functions * optimization: adding many (hundreds) methods to a generic function can be done faster.