* src/bignum.c (make_neg_biguint): New function.
* src/lread.c (read1): Do not mishandle an unquoted symbol
with name equal to something like "1\0x", i.e., a string
of numeric form followed by a NUL byte.
Formerly these symbols were misread as numbers.
(string_to_number): Change last argument from an integer flag
to a pointer to the length.  This lets the caller figure out
how much of the prefix was used.  All callers changed.
Add a fast path if the integer (sans sign) fits in uintmax_t.
Update comments and simplify now that bignums are present.
* src/print.c (print_object): Fix quoting of symbols that look
like numbers, by relying on string_to_number for the tricky
cases rather than trying to redo its logic, incorrectly.  For
example, (read (prin1-to-string '\1e+NaN)) formerly returned
"1e+NaN", which was wrong: a backslash is needed in the output
to prevent it from being read as a NaN.  Escape NO_BREAK_SPACE
too, since lread.c treats it like SPACE.
* test/src/print-tests.el (print-read-roundtrip):
Add tests illustrating the abovementioned bugs.

* src/bignum.c: Include stdlib.h, for abs.
(bignum_bufsize, bignum_to_c_string): New functions.
* src/bignum.c (bignum_to_string):
* src/print.c (print_vectorlike): Use them.
* src/editfns.c (styled_format): Instead of having a separate
buffer for sprintf (which does not work for bignums), just append
to the main buffer.  When formatting bignums, add support for the
standard integer flags -, #, 0, + and space.  Fix some comments.
Capitalize properly when formatting bignums with %X.  Use
functions like c_isdigit rather than reinventing the wheel.
Simplify computation of excess precision.
* src/print.c: Do not include bignum.h; no longer needed.
(print_vectorlike): Avoid recalculating string length.
* test/src/editfns-tests.el (format-bignum):
Test some of the above fixes.

* src/bignum.c, src/bignum.h: New files.  Only modules that
need to know how bignums are implemented should include
bignum.h.  Currently these are alloc.c, bignum.c (of course),
data.c, emacs.c, emacs-module.c, floatfns.c, fns.c, print.c.
* src/Makefile.in (base_obj): Add bignum.o.
* src/alloc.c (make_bignum_str): Move to bignum.c.
(make_number): Remove; replaced by bignum.c’s make_integer.
All callers changed.
* src/conf_post.h (ARG_NONNULL): New macro.
* src/json.c (json_to_lisp): Use it.
* src/data.c (Fnatnump):
Move NATNUMP’s implementation here from lisp.h.
* src/data.c (Fnumber_to_string):
* src/editfns.c (styled_format):
Move conversion of string to bignum to bignum_to_string, and
call it here.
* src/emacs-module.c (module_make_integer):
* src/floatfns.c (Fabs):
Simplify by using make_int.
* src/emacs.c: Include bignum.h, to expand its inline fns.
* src/floatfns.c (Ffloat): Simplify by using XFLOATINT.
(rounding_driver): Simplify by using double_to_bignum.
(rounddiv_q): Clarify use of temporaries.
* src/lisp.h: Move decls that need to know bignum internals to
bignum.h.  Do not include gmp.h or mini-gmp.h; that is now
bignum.h’s job.
(GMP_NUM_BITS, struct Lisp_Bignum, XBIGNUM, mpz_set_intmax):
Move to bignum.h.
(make_int): New function.
(NATNUMP): Remove; all callers changed to use Fnatnump.
(XFLOATINT): If arg is a bignum, use bignum_to_double, so that
bignum internals are not exposed here.
* src/print.c (print_vectorlike): Use SAFE_ALLOCA to avoid the
need for a record_unwind_protect_ptr.

Eliminate the category of miscellaneous objects, and turn all
such objects into pseudovectors.  The immediate motivation
for this change is to free up an enum Lisp_Type tag value, a
scarce resource that can be better used elsewhere.  However,
this change is worthwhile in its own right, as it improves
performance slightly on my platform, 0.3% faster for 'make
compile-always' on Fedora 28, and it simplifies the garbage
collector and interpreter (Bug#32405).
* doc/lispref/internals.texi (Garbage Collection):
* etc/NEWS:
Document change to garbage-collect return value.
* src/alloc.c (total_markers, total_free_markers):
(union aligned_Lisp_Misc, MARKER_BLOCK_SIZE)
(struct marker_block, marker_block, marker_block_index)
(misc_free_list, allocate_misc, live_misc_holding)
(live_misc_p, sweep_misc):
* src/lisp.h (lisp_h_MARKERP, lisp_h_MISCP, MARKERP, MISCP)
(Lisp_Misc, enum Lisp_Misc_Type, Lisp_Misc_Free)
(Lisp_Misc_Marker, Lisp_Misc_Overlay, Lisp_Misc_Finalizer)
(Lisp_Misc_Ptr, Lisp_Misc_User_Ptr, Lisp_Misc_Limit)
(Lisp_Misc_Bignum)
(XSETMISC, struct Lisp_Misc_Any, XMISCANY, XMISCTYPE)
(struct Lisp_Free, union Lisp_Misc, XMISC):
Remove.  All uses removed.
(cleanup_vector): Clean up objects that were formerly misc
and are now pseudovectors.
(make_misc_ptr, build_overlay, Fmake_marker, build_marker)
(make_bignum_str, make_number, make_pure_bignum)
(make_user_ptr, Fmake_finalizer):
Build as pseudovectors, not as misc objects.
(mark_finalizer_list, queue_doomed_finalizers)
(compact_undo_list, mark_overlay, mark_object)
(unchain_dead_markers):
Mark as vector-like objects, not as misc objects.
(mark_maybe_object, mark_maybe_pointer, valid_lisp_object_p)
(total_bytes_of_live_objects, survives_gc_p):
* src/fns.c (sxhash):
No need to worry about misc objects.
(garbage_collect_1): Do not generate a 'misc' component.
(syms_of_alloc): No need for 'misc' symbol.
* src/buffer.c (overlays_at, overlays_in, overlay_touches_p)
(overlay_strings, recenter_overlay_lists)
(fix_start_end_in_overlays, fix_overlays_before)
(Foverlay_lists, report_overlay_modification)
(evaporate_overlays):
* src/editfns.c (overlays_around):
* src/data.c (Ftype_of):
* src/fns.c (internal_equal):
* src/lisp.h (mint_ptrp, xmint_pointer, FINALIZERP)
(XFINALIZER, MARKERP, XMARKER, OVERLAYP, XOVERLAY, USER_PTRP)
(XUSER_PTR, BIGNUMP, XBIGNUM):
* src/print.c (print_vectorlike, print_object):
* src/undo.c (record_marker_adjustments):
* src/xdisp.c (load_overlay_strings):
Formerly misc objects are now pseudovectors.
* src/lisp.h (PVEC_MARKER, PVEC_OVERLAY, PVEC_FINALIZER)
(PVEC_BIGNUM, PVEC_MISC_PTR, PVEC_USER_PTR):
New constants, replacing their misc versions.  All uses changed.
(struct Lisp_Marker, struct Lisp_Overlay, struct Lisp_Misc_Ptr)
(struct Lisp_Bignum, struct Lisp_User_Ptr, struct Lisp_Finalizer):
Make usable as a pseudovector by using a pseudovector header,
replacing any DIY components, and putting Lisp_Object members
first.  All uses changed.

* src/alloc.c, src/bidi.c, src/buffer.c, src/buffer.h, src/bytecode.c,
src/callint.c, src/callproc.c, src/casefiddle.c, src/casetab.c,
src/category.c, src/ccl.c, src/character.c, src/character.h,
src/charset.c, src/charset.h, src/chartab.c, src/cmds.c, src/coding.c,
src/composite.c, src/composite.h, src/data.c, src/dbusbind.c,
src/decompress.c, src/dired.c, src/dispextern.h, src/dispnew.c,
src/disptab.h, src/doc.c, src/dosfns.c, src/editfns.c,
src/emacs-module.c, src/emacs.c, src/eval.c, src/fileio.c,
src/floatfns.c, src/fns.c, src/font.c, src/font.h, src/fontset.c,
src/frame.c, src/frame.h, src/fringe.c, src/ftcrfont.c, src/ftfont.c,
src/gfilenotify.c, src/gnutls.c, src/gtkutil.c, src/image.c,
src/indent.c, src/insdel.c, src/intervals.c, src/json.c,
src/keyboard.c, src/keymap.c, src/kqueue.c, src/lcms.c, src/lisp.h,
src/lread.c, src/macros.c, src/marker.c, src/menu.c, src/minibuf.c,
src/msdos.c, src/print.c, src/process.c, src/profiler.c, src/search.c,
src/sound.c, src/syntax.c, src/syntax.h, src/sysdep.c, src/term.c,
src/termhooks.h, src/textprop.c, src/undo.c, src/w32.c,
src/w32console.c, src/w32fns.c, src/w32font.c, src/w32inevt.c,
src/w32proc.c, src/w32select.c, src/w32term.c, src/w32term.h,
src/w32uniscribe.c, src/window.c, src/xdisp.c, src/xfaces.c,
src/xfns.c, src/xfont.c, src/xftfont.c, src/xmenu.c, src/xml.c,
src/xrdb.c, src/xselect.c, src/xsettings.c, src/xterm.c, src/xwidget.c
Rename XINT->XFIXNUM, XFASTINT->XFIXNAT, XUINT->XUFIXNUM.

* .gitignore: Add lib/ieee754.h.
* admin/merge-gnulib (GNULIB_MODULES): Add ieee754-h.
* configure.ac: Remove ieee754.h check, as Gnulib now does that.
* etc/NEWS: Mention this.
* lib/gnulib.mk.in, m4/gnulib-comp.m4: Regenerate.
* lib/ieee754.in.h, m4/ieee754-h.m4: New files, from Gnulib.
* src/lisp.h (IEEE_FLOATING_POINT): Now a macro so that it
can be used in #if.
* src/lread.c, src/print.c: Include <ieee754.h> if
IEEE_FLOATING_POINT, not if HAVE_IEEE754_H.
* src/lread.c (string_to_number):
* src/print.c (float_to_string):
Process NaNs only on IEEE hosts, and assume <ieee754.h>
in that case.

* configure.ac: Check for ieee754.h.
* doc/lispref/numbers.texi (Float Basics): Document
that NaN string representation digits are machine-dependent.
* etc/NEWS: Mention the change.
* src/lread.c, src/print.c [HAVE_IEEE754_H]: Include ieee754.h.
* src/lread.c (string_to_number) [HAVE_IEEE754_H]:
* src/print.c (float_to_string) [HAVE_IEEE754_H]:
Read and print NaN significand.

These should be portable nowadays.
* src/data.c (isnan): Remove.
* src/floatfns.c (isfinite, isnan): Remove.
* src/print.c: Include math.h, for isinf and isnan.
(float_to_string): Simplify by using them.

* src/alloc.c (mark_object): Handle Lisp_Misc_Bignum.
(sweep_misc): Call mpz_clear for Lisp_Misc_Bignum.
* src/data.c (Ftype_of): Handle Lisp_Misc_Bignum.
(Fintegerp, Finteger_or_marker_p, Fnatnump, Fnumberp)
(Fnumber_or_marker_p): Update for bignum.
(Ffixnump, Fbignump): New defuns.
(syms_of_data): Update.
* src/emacs.c (xrealloc_for_gmp, xfree_for_gmp): New functions.
(main): Call mp_set_memory_functions.
* src/lisp.h (enum Lisp_Misc_Type) <Lisp_Misc_Bignum>: New constant.
(struct Lisp_Bignum): New.
(union Lisp_Misc): Add u_bignum.
(BIGNUMP, XBIGNUM, INTEGERP, NATNUMP, NUMBERP, CHECK_NUMBER)
(CHECK_INTEGER, CHECK_NUMBER_COERCE_MARKER): New functions.
* src/print.c (print_object): Handle Lisp_Misc_Bignum.