Update to Gforth 0.7.0.

User-visible changes between 0.6.2 and 0.7.0:

Requirements:
  At run-time requires libtool and gcc (for the libcc C interface) and
                       gdb (for the disassembler (SEE)) on some platforms.
License:
  Changed to GPLv3
Bug fixes
  Now works with address-space randomization.
  The single-step debugger works again in some engines.
  Many others.
Ports:
  AMD64, ARM, IA-64 (Itanium): better performance
  PPC, PPC64: disassembler and assembler
  Gforth EC: R8C, 4stack, misc, 8086 work
  MacOS X: better support
Invocation:
  New flags --ignore-async-signals, --vm-commit (default overcommit)
            --print-sequences
Forth 200x:
  X:extension-query: produce true for all implemented extensions
  X:required REQUIRED etc. (not new)
  X:defined: [DEFINED] and [UNDEFINED]
  X:parse-name: PARSE-NAME (new name)
  X:deferred: deferred words (new: DEFER@ DEFER! ACTION-OF)
  X:structures: +FIELD FIELD: FFIELD: CFIELD: etc.
  X:ekeys: new: EKEY>FKEY K-SHIFT-MASK K-CTRL-MASK K-ALT-MASK K-F1...K-F12
  X:fp-stack (not new)
  X:number-prefixes (partially new, see below)
Number prefixes:
  0x is a hex prefix: 0xff and 0XfF now produces (decimal) 255
  # is a decimal prefix: #10 now produces (decimal) 10
  Signs after the number prefix are now accepted, e.g, #-50.
  ' now only handles a single (x)char: 'ab is no longer accepted,
                                       'a' now produces (decimal) 97
Unicode support (currently supports only uniform encoding):
  added xchars words for dealing with variable-width multi-byte characters
  provide 8bit (ISO Latin 1) and UTF-8 support for xchars
New words:
  \C C-FUNCTION C-LIBRARY END-C-LIBRARY C-LIBRARY-NAME (libcc C interface)
  LIB-ERROR (complements OPEN-LIB)
  OUTFILE-EXECUTE INFILE-EXECUTE BASE-EXECUTE (limited change of global state)
  16-bit and 32-bit memory acces: UW@ UL@ SW@ SL@ W! L! W@ L@ /W /L
  NEXT-ARG SHIFT-ARGS (OS command-line argument processing)
  NOTHROW (for backtrace control)
  FTRUNC FMOD (undocumented)
  SEE-CODE SEE-CODE-RANGE (show generated dynamic native code)
Improvements/changes of existing words:
  S\", .\" now support \l, \m, \z, and limits hex and octal character specs.
  OPEN-FILE with W/O no longer creates or truncates files (no compat. file)
  OPEN-LIB now understands ~ at the start, like OPEN-FILE.
  TRY...ENDTRY changed significantly, compatibility files available (see docs).
  The disassembler (DISCODE) can now use gdb to disassemble code
  Uninitialized defered words now give a warning when executed
  Division is floored (disable with "configure --enable-force-cdiv")
  Gforth (not gforth-fast) reports division by zero and overflow on division
    on all platforms.
Newly documented words:
  S>NUMBER? S>UNUMBER?
  EKEY keypress names: K-LEFT  K-RIGHT K-UP K-DOWN K-HOME K-END K-PRIOR
    K-NEXT K-INSERT K-DELETE
  CLEARSTACKS
  FORM
Environment variable GFORTHSYSTEMPREFIX (used by word SYSTEM and friends)
C interface:
  exported symbols now start with "gforth_" (for referencing them from C code)
  libcc C function call interface (requires libtool and gcc at run-time)
    alternative: undocumented libffi-based interface
Libraries:
  depth-changes.fs: report stack depth changes during interpretation
  ans-report.fs now reports CfV extensions
  fsl-util.4th: FSL support files (undocumented)
  regexp.fs for regular expressions (undocumented)
  complex.fs for complex numbers (undocumented)
  fft.fs for Fast Fourier Transform (undocumented)
  wf.fs, a Wiki implementation (undocumented)
  httpd.fs, a web server (undocumented)
  status.fs, show interpreter status in separate xterm (undocumented)
  profile.fs for profiling (undocumented, incomplete)
  endtry-iferror.fs, recover-endtry.fs to ease the TRY change transition
  test/tester.fs: Now works with FP numbers (undocumented)
  test/ttester.fs: Version of tester.fs with improved interface (T{...}T).
 compat library:
  compat/execute-parsing.fs
Speed improvements:
  automatic performance tuning on building
  static stack caching (good speedup on PPC)
  mixed-precision division is now faster
  support for int128 types on AMD64
  workarounds for gcc performance bugs (in particular, PR 15242)
  branch target alignment (good speedup on Alpha).


(asau)