Log Message:
Update to sbcl 2.3.8.

Add dependency on devel/gmp.
Set MKPIE_SUPPORTED to no.

Changes in sbcl-2.3.8 relative to sbcl-2.3.7

    * enhancement: a mark-region parallel garbage collector is
      available as a build-time option; it can be enabled by adding
      `--without-gencgc --with-mark-region-gc` to the build command
      line. (Thanks to Hayley Patton)
    * enhancement: Stack allocation via DYNAMIC-EXTENT is now possible
      for conditionals even when not all branches are
      stack-allocatable. Previously all branches needed to be
      stack-allocatable for the otherwise-inaccessible subparts to get
      stack allocated.
    * platform support:
        * on Mac OS X Sonoma, loading the memory image no longer
          fails. (#2029430, reported by cladur)
        * on Darwin, we no longer reimplement nanosleep().
        * on PPC64, undefined function errors now work.
        * on ARM64/OpenBSD, enable the GCC TLS feature. (thanks to
          Sébastien Marie)
        * when building the system, only display a reasonable amount
          of timing precision. (thanks to Philipp Marek)
    * bug fix: handling of inlining functions compiled to return
      unboxed values no longer crashes the compiler. (#2029020,
      reported by Pascal J. Bourguignon)
    * bug fix: the source location for code executed within a
      top-level (EVAL-WHEN (:COMPILE-TOPLEVEL) ...) form is now more
      useful.
    * bug fix: address a race between user threads cancelling
      finalizers and the finalizer thread executing them. (#2029306)
    * bug fix: complex division returns the same value when evaluated
      inline and out-of-line. (#2030097)
    * bug fix: the pretty-printer no longer deletes
      syntactically-significant whitespace immediately preceding a
      newline. (#1985814, reported by Mark David)
    * optimization: the compiler is more aware of the result type of
      the NUMERATOR function.
    * optimization: EQUAL and EQUALP compile to more efficient code
      when the two arguments are known to be of the same nullable
      type.
    * optimization: converting bignums to floats uses no intermediate memory.

Changes in sbcl-2.3.7 relative to sbcl-2.3.6

    * minor incompatible change: MACROLET macro functions are now
      compiled with (SPEED 1), leading to fewer efficiency notes being
      emitted when compiled in otherwise high-SPEED environments.
    * minor incompatible change: when coalescing list data, the file
      compiler respects substructure equality more accurately, with
      the side-effect of coalescing along CDR chains as well as
      CARs. (#2025086)
    * minor incompatible change: FUNCTION type declarations for local
      variables generate assertions around their use when called.
    * platform support
        * on OpenBSD, the regression test suite expectations have been
          updated. (#2026809, thanks to Sebastien Marie)
        * on OpenBSD, the data limit is now 1GB. (#2027536, thanks to
          Sebastien Marie)
        * on Darwin with the SB-FUTEX feature, do not use unpaired
          mach_thread_self() syscalls, avoiding resource leaks when
          creating threads.
        * on 64-bit RISCV, add support for some REM-by-multiplication
          optimizations.
        * on Windows, work around a C compiler bug relating to SYSV_ABI.
    * bug fix: FILE-POSITION on string output streams no longer
      crashes or causes arbitrary memory overwrites. (#1839040)
    * bug fix: the compiler no longer constant-folds POSITION to NIL
      if the START or END arguments are not valid.
    * optimization: the compiler derives types of &KEY arguments in
      local calls. (#655562)
    * optimization: type tests of values of known union type can be
      faster if the type being tested for has a non-trivial
      intersection with the known type.
    * optimization: the low-level implementation of NUMBERP, REALP and
      RATIONALP has been improved on x86-64 and arm64.
    * optimization: the compiler removes known-NIL arguments from
      calls to APPEND and NCONC, and empty sequences from calls to
      CONCATENATE.
    * optimization: checks for symbols being bindable are now
      memoized, speeding up compiled uses of PROGV.
    * optimization: SLOT-VALUE on STRUCTURE-OBJECTs with non-constant
      slot-name argument is faster.