update from main archive 961207cvs/libc-961208

Sun Dec  8 06:56:49 1996  Ulrich Drepper  <drepper@cygnus.com>

	* io/getwd.c: Use PATH_MAX not LOCAL_PATH_MAX.  Fix typo in
	comment.
	* stdlib/canonicalize.c: Correct bugs in last change.
	Patch by HJ Lu.

	* libio/Makefile (routines): Remove ioprims.
	(aux): Remove cleanup.
	Add IO_DEBUG option for .o files.
	* libio/cleanups.c: Removed.
	* libio/ioprims.c: Removed.
	* libio/filedoalloc.c: More updates from libg++-2.8b5.
	* libio/fileops.c: Likewise.
	* libio/genops.c: Likewise.
	* libio/iolibio.h: Likewise.
	* libio/iopopen.c: Likewise.
	* libio/iovsprintf.c: Likewise.
	* libio/iovsscanf.c: Likewise.
	* libio/libio.h: Likewise.
	* libio/libioP.h: Likewise.
	* libio/memstream.c: Likewise.
	* libio/strfile.h: Likewise.
	* libio/vasprintf.c: Likewise.
	* libio/vsnprintf.c: Likewise.

	* libio/stdio.h: Define P_tmpdir only is __USE_SVID.

	* manual/arith.texi: Change references to ANSI C to ISO C.
	* manual/conf.texi: Likewise.
	* manual/creature.texi: Likewise.
	* manual/ctype.texi: Likewise.
	* manual/errno.texi: Likewise.
	* manual/filesys.texi: Likewise.
	* manual/intro.texi. Likewise.
	* manual/io.texi: Likewise.
	* manual/lang.texi: Likewise.
	* manual/libc.texinfo: Likewise.
	* manual/locale.texi: Likewise.
	* manual/maint.texi: Likewise.
	* manual/mbyte.texi: Likewise.
	* manual/memory.texi: Likewise.
	* manual/process.texi: Likewise.
	* manual/process.texi: Likewise.
	* manual/search.texi: Likewise.
	* manual/setjmp.texi: Likewise.
	* manual/signal.texi: Likewise.
	* manual/startup.texi: Likewise.
	* manual/stdio.texi: Likewise.
	* manual/string.texi: Likewise.
	* manual/time.texi: Likewise.

	* manual/locale.texi: Remove description of LC_RESPONSE and add
	LC_MESSAGES.

	* Makefile (subdirs): Change malloc in $(malloc).
	* config.make.in: Add variable malloc which is initialized from
	@malloc@.
	* configure.in: Add new option --enable-new-malloc to use new
	malloc.  This is the default on Linux.
	* sysdeps/unix/sysv/linux/configure.in: Define malloc to new-malloc
	by default.
	* new-malloc/Makefile: New file.  Improved malloc implementation.
	* new-malloc/malloc.c: Likewise.
	* new-malloc/malloc.h: Likewise.
	* new-malloc/mallocbug.c: Likewise.
	* new-malloc/obstack.c: Likewise.
	* new-malloc/obstack.h: Likewise.
	* new-malloc/thread-m.h: Likewise.
	* time/Makefile: Compile ap.c with NO_MCHECK flag for now.
	* time/ap.c: Don't call mcheck if NO_MCHECK is defined.

	* resolv/Makefile: Add rule to rebuiild libresolv.so when libc.so
	changed.

	* stdio/feof.c: Update copyright.
	* stdio/stdio.h: Add field for lock to FILE structure.
	Add cast to *MAGIC constants to prevent warnings.

	* stdio-common/bug7.c: Correct test.  Stream must not be closed
	twice.

	* stdlib/Makefile (routines): Add secure-getenv.
	* stdlib/secure-getenv.c: New file.  __secure_getenv function
	moved to here from sysdeps/generic/getenv.c.  Otherwise an
	application cannot replace the getenv function in the libc.
	* sysdeps/generic/getenv.c: Remove __secure_getenv function.
	* sysdeps/stub/getenv.c: Remove __secure_getenv alias.

	* sysdeps/mach/libc-lock.h: Define__libc_mutex_lock to __mutex_lock.

	* sysdeps/posix/fdopen.c: Update copyright.  Don't use EXFUN.

	* time/test-tz.c: Comment fifth test out.  PROBLEM.

	* time/tzset.c: De-ANSI-declfy.
	(__tzset): Don't increment pointer tz when no DST information is
	given.

Sat Dec  7 23:47:54 1996  Ulrich Drepper  <drepper@cygnus.com>

	* sysdeps/mach/libc-lock.h [_LIBC]: Add definition of
	__libc_mutex_lock.
	Patch by Thomas Bushnell.

	* sysdeps/unix/sysv/linux/timebits.h: Load <asm/param.h> only
	if __USE_MISC.

	* sysdeps/unix/sysv/linux/Dist: Add llseek.c.

Sat Dec  7 12:18:56 1996  Ulrich Drepper  <drepper@cygnus.com>

	* time/strftime (%c format): Remove %Z from default string.
	Reported by Paul Eggert

	* io/getwd.c: Don't apply getcwd on user supplied buffer.

7 files changed, 5021 insertions, 0 deletions

diff --git a/malloc/Makefile b/malloc/Makefile
new file mode 100644
index 0000000000..a6213949e1
--- /dev/null
+++ b/malloc/Makefile
@@ -0,0 +1,40 @@
+# Copyright (C) 1991, 92, 93, 94, 95, 96 Free Software Foundation, Inc.
+# This file is part of the GNU C Library.
+
+# The GNU C Library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Library General Public License as
+# published by the Free Software Foundation; either version 2 of the
+# License, or (at your option) any later version.
+
+# The GNU C Library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Library General Public License for more details.
+
+# You should have received a copy of the GNU Library General Public
+# License along with the GNU C Library; see the file COPYING.LIB.  If not,
+# write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+# Boston, MA 02111-1307, USA.
+
+#
+#	Makefile for malloc routines
+#
+subdir	:= new-malloc
+
+all:
+
+dist-headers := malloc.h
+headers := $(dist-headers) obstack.h
+tests := mallocbug
+
+distribute = thread-m.h
+
+# Things which get pasted together into gmalloc.c.
+gmalloc-routines := malloc morecore
+# Things to include in the standalone distribution.
+dist-routines = $(gmalloc-routines)
+routines = $(dist-routines) obstack
+
+include ../Rules
+
+CFLAGS-obstack.c = -Wno-strict-prototypes
diff --git a/malloc/malloc.c b/malloc/malloc.c
new file mode 100644
index 0000000000..ed24d5d76d
--- /dev/null
+++ b/malloc/malloc.c
@@ -0,0 +1,3443 @@
+/* Malloc implementation for multiple threads without lock contention.
+   Copyright (C) 1996 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Wolfram Gloger <wmglo@dent.med.uni-muenchen.de>, 1996.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+/* VERSION 2.6.4-pt Wed Dec  4 00:35:54 MET 1996
+
+  This work is mainly derived from malloc-2.6.4 by Doug Lea
+  <dl@cs.oswego.edu>, which is available from:
+
+                 ftp://g.oswego.edu/pub/misc/malloc.c
+
+  Most of the original comments are reproduced in the code below.
+
+* Why use this malloc?
+
+  This is not the fastest, most space-conserving, most portable, or
+  most tunable malloc ever written. However it is among the fastest
+  while also being among the most space-conserving, portable and tunable.
+  Consistent balance across these factors results in a good general-purpose
+  allocator. For a high-level description, see
+     http://g.oswego.edu/dl/html/malloc.html
+
+  On many systems, the standard malloc implementation is by itself not
+  thread-safe, and therefore wrapped with a single global lock around
+  all malloc-related functions.  In some applications, especially with
+  multiple available processors, this can lead to contention problems
+  and bad performance.  This malloc version was designed with the goal
+  to avoid waiting for locks as much as possible.  Statistics indicate
+  that this goal is achieved in many cases.
+
+* Synopsis of public routines
+
+  (Much fuller descriptions are contained in the program documentation below.)
+
+  ptmalloc_init();
+     Initialize global configuration.  When compiled for multiple threads,
+     this function must be called once before any other function in the
+     package.  It is not required otherwise. It is called automatically
+     in the Linux/GNU C libray.
+  malloc(size_t n);
+     Return a pointer to a newly allocated chunk of at least n bytes, or null
+     if no space is available.
+  free(Void_t* p);
+     Release the chunk of memory pointed to by p, or no effect if p is null.
+  realloc(Void_t* p, size_t n);
+     Return a pointer to a chunk of size n that contains the same data
+     as does chunk p up to the minimum of (n, p's size) bytes, or null
+     if no space is available. The returned pointer may or may not be
+     the same as p. If p is null, equivalent to malloc.  Unless the
+     #define REALLOC_ZERO_BYTES_FREES below is set, realloc with a
+     size argument of zero (re)allocates a minimum-sized chunk.
+  memalign(size_t alignment, size_t n);
+     Return a pointer to a newly allocated chunk of n bytes, aligned
+     in accord with the alignment argument, which must be a power of
+     two.
+  valloc(size_t n);
+     Equivalent to memalign(pagesize, n), where pagesize is the page
+     size of the system (or as near to this as can be figured out from
+     all the includes/defines below.)
+  pvalloc(size_t n);
+     Equivalent to valloc(minimum-page-that-holds(n)), that is,
+     round up n to nearest pagesize.
+  calloc(size_t unit, size_t quantity);
+     Returns a pointer to quantity * unit bytes, with all locations
+     set to zero.
+  cfree(Void_t* p);
+     Equivalent to free(p).
+  malloc_trim(size_t pad);
+     Release all but pad bytes of freed top-most memory back
+     to the system. Return 1 if successful, else 0.
+  malloc_usable_size(Void_t* p);
+     Report the number usable allocated bytes associated with allocated
+     chunk p. This may or may not report more bytes than were requested,
+     due to alignment and minimum size constraints.
+  malloc_stats();
+     Prints brief summary statistics on stderr.
+  mallinfo()
+     Returns (by copy) a struct containing various summary statistics.
+  mallopt(int parameter_number, int parameter_value)
+     Changes one of the tunable parameters described below. Returns
+     1 if successful in changing the parameter, else 0.
+
+* Vital statistics:
+
+  Alignment:                            8-byte
+       8 byte alignment is currently hardwired into the design.  This
+       seems to suffice for all current machines and C compilers.
+
+  Assumed pointer representation:       4 or 8 bytes
+       Code for 8-byte pointers is untested by me but has worked
+       reliably by Wolfram Gloger, who contributed most of the
+       changes supporting this.
+
+  Assumed size_t  representation:       4 or 8 bytes
+       Note that size_t is allowed to be 4 bytes even if pointers are 8.
+
+  Minimum overhead per allocated chunk: 4 or 8 bytes
+       Each malloced chunk has a hidden overhead of 4 bytes holding size
+       and status information.
+
+  Minimum allocated size: 4-byte ptrs:  16 bytes    (including 4 overhead)
+                          8-byte ptrs:  24/32 bytes (including, 4/8 overhead)
+
+       When a chunk is freed, 12 (for 4byte ptrs) or 20 (for 8 byte
+       ptrs but 4 byte size) or 24 (for 8/8) additional bytes are
+       needed; 4 (8) for a trailing size field
+       and 8 (16) bytes for free list pointers. Thus, the minimum
+       allocatable size is 16/24/32 bytes.
+
+       Even a request for zero bytes (i.e., malloc(0)) returns a
+       pointer to something of the minimum allocatable size.
+
+  Maximum allocated size: 4-byte size_t: 2^31 -  8 bytes
+                          8-byte size_t: 2^63 - 16 bytes
+
+       It is assumed that (possibly signed) size_t bit values suffice to
+       represent chunk sizes. `Possibly signed' is due to the fact
+       that `size_t' may be defined on a system as either a signed or
+       an unsigned type. To be conservative, values that would appear
+       as negative numbers are avoided.
+       Requests for sizes with a negative sign bit will return a
+       minimum-sized chunk.
+
+  Maximum overhead wastage per allocated chunk: normally 15 bytes
+
+       Alignnment demands, plus the minimum allocatable size restriction
+       make the normal worst-case wastage 15 bytes (i.e., up to 15
+       more bytes will be allocated than were requested in malloc), with
+       two exceptions:
+         1. Because requests for zero bytes allocate non-zero space,
+            the worst case wastage for a request of zero bytes is 24 bytes.
+         2. For requests >= mmap_threshold that are serviced via
+            mmap(), the worst case wastage is 8 bytes plus the remainder
+            from a system page (the minimal mmap unit); typically 4096 bytes.
+
+* Limitations
+
+    Here are some features that are NOT currently supported
+
+    * No user-definable hooks for callbacks and the like.
+    * No automated mechanism for fully checking that all accesses
+      to malloced memory stay within their bounds.
+    * No support for compaction.
+
+* Synopsis of compile-time options:
+
+    People have reported using previous versions of this malloc on all
+    versions of Unix, sometimes by tweaking some of the defines
+    below. It has been tested most extensively on Solaris and
+    Linux. People have also reported adapting this malloc for use in
+    stand-alone embedded systems.
+
+    The implementation is in straight, hand-tuned ANSI C.  Among other
+    consequences, it uses a lot of macros.  Because of this, to be at
+    all usable, this code should be compiled using an optimizing compiler
+    (for example gcc -O2) that can simplify expressions and control
+    paths.
+
+  __STD_C                  (default: derived from C compiler defines)
+     Nonzero if using ANSI-standard C compiler, a C++ compiler, or
+     a C compiler sufficiently close to ANSI to get away with it.
+  MALLOC_DEBUG             (default: NOT defined)
+     Define to enable debugging. Adds fairly extensive assertion-based
+     checking to help track down memory errors, but noticeably slows down
+     execution.
+  REALLOC_ZERO_BYTES_FREES (default: NOT defined)
+     Define this if you think that realloc(p, 0) should be equivalent
+     to free(p). Otherwise, since malloc returns a unique pointer for
+     malloc(0), so does realloc(p, 0).
+  HAVE_MEMCPY               (default: defined)
+     Define if you are not otherwise using ANSI STD C, but still
+     have memcpy and memset in your C library and want to use them.
+     Otherwise, simple internal versions are supplied.
+  USE_MEMCPY               (default: 1 if HAVE_MEMCPY is defined, 0 otherwise)
+     Define as 1 if you want the C library versions of memset and
+     memcpy called in realloc and calloc (otherwise macro versions are used).
+     At least on some platforms, the simple macro versions usually
+     outperform libc versions.
+  HAVE_MMAP                 (default: defined as 1)
+     Define to non-zero to optionally make malloc() use mmap() to
+     allocate very large blocks.
+  HAVE_MREMAP                 (default: defined as 0 unless Linux libc set)
+     Define to non-zero to optionally make realloc() use mremap() to
+     reallocate very large blocks.
+  malloc_getpagesize        (default: derived from system #includes)
+     Either a constant or routine call returning the system page size.
+  HAVE_USR_INCLUDE_MALLOC_H (default: NOT defined)
+     Optionally define if you are on a system with a /usr/include/malloc.h
+     that declares struct mallinfo. It is not at all necessary to
+     define this even if you do, but will ensure consistency.
+  INTERNAL_SIZE_T           (default: size_t)
+     Define to a 32-bit type (probably `unsigned int') if you are on a
+     64-bit machine, yet do not want or need to allow malloc requests of
+     greater than 2^31 to be handled. This saves space, especially for
+     very small chunks.
+  _LIBC                     (default: NOT defined)
+     Defined only when compiled as part of the Linux libc/glibc.
+     Also note that there is some odd internal name-mangling via defines
+     (for example, internally, `malloc' is named `mALLOc') needed
+     when compiling in this case. These look funny but don't otherwise
+     affect anything.
+  LACKS_UNISTD_H            (default: undefined)
+     Define this if your system does not have a <unistd.h>.
+  MORECORE                  (default: sbrk)
+     The name of the routine to call to obtain more memory from the system.
+  MORECORE_FAILURE          (default: -1)
+     The value returned upon failure of MORECORE.
+  MORECORE_CLEARS           (default 1)
+     True (1) if the routine mapped to MORECORE zeroes out memory (which
+     holds for sbrk).
+  DEFAULT_TRIM_THRESHOLD
+  DEFAULT_TOP_PAD
+  DEFAULT_MMAP_THRESHOLD
+  DEFAULT_MMAP_MAX
+     Default values of tunable parameters (described in detail below)
+     controlling interaction with host system routines (sbrk, mmap, etc).
+     These values may also be changed dynamically via mallopt(). The
+     preset defaults are those that give best performance for typical
+     programs/systems.
+
+
+*/
+
+/*
+
+* Compile-time options for multiple threads:
+
+  USE_PTHREADS, USE_THR, USE_SPROC
+     Define one of these as 1 to select the thread interface:
+     POSIX threads, Solaris threads or SGI sproc's, respectively.
+     If none of these is defined as non-zero, you get a `normal'
+     malloc implementation which is not thread-safe.  Support for
+     multiple threads requires HAVE_MMAP=1.  As an exception, when
+     compiling for GNU libc, i.e. when _LIBC is defined, then none of
+     the USE_... symbols have to be defined.
+
+  HEAP_MIN_SIZE
+  HEAP_MAX_SIZE
+     When thread support is enabled, additional `heap's are created
+     with mmap calls.  These are limited in size; HEAP_MIN_SIZE should
+     be a multiple of the page size, while HEAP_MAX_SIZE must be a power
+     of two for alignment reasons.  HEAP_MAX_SIZE should be at least
+     twice as large as the mmap threshold.
+  THREAD_STATS
+     When this is defined as non-zero, some statistics on mutex locking
+     are computed.
+
+*/
+
+
+
+
+/* Macros for handling mutexes and thread-specific data.  This is
+   included first, because some thread-related header files (such as
+   pthread.h) should be included before any others. */
+#include "thread-m.h"
+
+
+/* Preliminaries */
+
+#ifndef __STD_C
+#if defined (__STDC__)
+#define __STD_C     1
+#else
+#if __cplusplus
+#define __STD_C     1
+#else
+#define __STD_C     0
+#endif /*__cplusplus*/
+#endif /*__STDC__*/
+#endif /*__STD_C*/
+
+#ifndef Void_t
+#if __STD_C
+#define Void_t      void
+#else
+#define Void_t      char
+#endif
+#endif /*Void_t*/
+
+#if __STD_C
+#include <stddef.h>   /* for size_t */
+#else
+#include <sys/types.h>
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdio.h>    /* needed for malloc_stats */
+
+
+/*
+  Compile-time options
+*/
+
+
+/*
+    Debugging:
+
+    Because freed chunks may be overwritten with link fields, this
+    malloc will often die when freed memory is overwritten by user
+    programs.  This can be very effective (albeit in an annoying way)
+    in helping track down dangling pointers.
+
+    If you compile with -DMALLOC_DEBUG, a number of assertion checks are
+    enabled that will catch more memory errors. You probably won't be
+    able to make much sense of the actual assertion errors, but they
+    should help you locate incorrectly overwritten memory.  The
+    checking is fairly extensive, and will slow down execution
+    noticeably. Calling malloc_stats or mallinfo with MALLOC_DEBUG set will
+    attempt to check every non-mmapped allocated and free chunk in the
+    course of computing the summmaries. (By nature, mmapped regions
+    cannot be checked very much automatically.)
+
+    Setting MALLOC_DEBUG may also be helpful if you are trying to modify
+    this code. The assertions in the check routines spell out in more
+    detail the assumptions and invariants underlying the algorithms.
+
+*/
+
+#if MALLOC_DEBUG
+#include <assert.h>
+#else
+#define assert(x) ((void)0)
+#endif
+
+
+/*
+  INTERNAL_SIZE_T is the word-size used for internal bookkeeping
+  of chunk sizes. On a 64-bit machine, you can reduce malloc
+  overhead by defining INTERNAL_SIZE_T to be a 32 bit `unsigned int'
+  at the expense of not being able to handle requests greater than
+  2^31. This limitation is hardly ever a concern; you are encouraged
+  to set this. However, the default version is the same as size_t.
+*/
+
+#ifndef INTERNAL_SIZE_T
+#define INTERNAL_SIZE_T size_t
+#endif
+
+/*
+  REALLOC_ZERO_BYTES_FREES should be set if a call to
+  realloc with zero bytes should be the same as a call to free.
+  Some people think it should. Otherwise, since this malloc
+  returns a unique pointer for malloc(0), so does realloc(p, 0).
+*/
+
+
+/*   #define REALLOC_ZERO_BYTES_FREES */
+
+
+/*
+  HAVE_MEMCPY should be defined if you are not otherwise using
+  ANSI STD C, but still have memcpy and memset in your C library
+  and want to use them in calloc and realloc. Otherwise simple
+  macro versions are defined here.
+
+  USE_MEMCPY should be defined as 1 if you actually want to
+  have memset and memcpy called. People report that the macro
+  versions are often enough faster than libc versions on many
+  systems that it is better to use them.
+
+*/
+
+#define HAVE_MEMCPY
+
+#ifndef USE_MEMCPY
+#ifdef HAVE_MEMCPY
+#define USE_MEMCPY 1
+#else
+#define USE_MEMCPY 0
+#endif
+#endif
+
+#if (__STD_C || defined(HAVE_MEMCPY))
+
+#if __STD_C
+void* memset(void*, int, size_t);
+void* memcpy(void*, const void*, size_t);
+#else
+Void_t* memset();
+Void_t* memcpy();
+#endif
+#endif
+
+#if USE_MEMCPY
+
+/* The following macros are only invoked with (2n+1)-multiples of
+   INTERNAL_SIZE_T units, with a positive integer n. This is exploited
+   for fast inline execution when n is small. */
+
+#define MALLOC_ZERO(charp, nbytes)                                            \
+do {                                                                          \
+  INTERNAL_SIZE_T mzsz = (nbytes);                                            \
+  if(mzsz <= 9*sizeof(mzsz)) {                                                \
+    INTERNAL_SIZE_T* mz = (INTERNAL_SIZE_T*) (charp);                         \
+    if(mzsz >= 5*sizeof(mzsz)) {     *mz++ = 0;                               \
+                                     *mz++ = 0;                               \
+      if(mzsz >= 7*sizeof(mzsz)) {   *mz++ = 0;                               \
+                                     *mz++ = 0;                               \
+        if(mzsz >= 9*sizeof(mzsz)) { *mz++ = 0;                               \
+                                     *mz++ = 0; }}}                           \
+                                     *mz++ = 0;                               \
+                                     *mz++ = 0;                               \
+                                     *mz   = 0;                               \
+  } else memset((charp), 0, mzsz);                                            \
+} while(0)
+
+#define MALLOC_COPY(dest,src,nbytes)                                          \
+do {                                                                          \
+  INTERNAL_SIZE_T mcsz = (nbytes);                                            \
+  if(mcsz <= 9*sizeof(mcsz)) {                                                \
+    INTERNAL_SIZE_T* mcsrc = (INTERNAL_SIZE_T*) (src);                        \
+    INTERNAL_SIZE_T* mcdst = (INTERNAL_SIZE_T*) (dest);                       \
+    if(mcsz >= 5*sizeof(mcsz)) {     *mcdst++ = *mcsrc++;                     \
+                                     *mcdst++ = *mcsrc++;                     \
+      if(mcsz >= 7*sizeof(mcsz)) {   *mcdst++ = *mcsrc++;                     \
+                                     *mcdst++ = *mcsrc++;                     \
+        if(mcsz >= 9*sizeof(mcsz)) { *mcdst++ = *mcsrc++;                     \
+                                     *mcdst++ = *mcsrc++; }}}                 \
+                                     *mcdst++ = *mcsrc++;                     \
+                                     *mcdst++ = *mcsrc++;                     \
+                                     *mcdst   = *mcsrc  ;                     \
+  } else memcpy(dest, src, mcsz);                                             \
+} while(0)
+
+#else /* !USE_MEMCPY */
+
+/* Use Duff's device for good zeroing/copying performance. */
+
+#define MALLOC_ZERO(charp, nbytes)                                            \
+do {                                                                          \
+  INTERNAL_SIZE_T* mzp = (INTERNAL_SIZE_T*)(charp);                           \
+  long mctmp = (nbytes)/s