bcopy -> memcpy/memmove transition proposal

[Per Bothner <bothner at cygnus dot com>]

It is really ridiculous that gcc still uses the non-ANSI functions
(such as bcopy), rather than the standard ANSI functions.  We all
(I hope) agree this is bogus, but fixing them all is a hassle.
Here is a concrete suggestion for how we can deal with a mix
of both styles, and fix them as convenient.

1) Add memcpy, memmove, memzero, strchr, and strrchr to
the list of functions in the AC_CHECK_FUNCS macro in configure.in.

2) Add a new file string.c, which is always linked in.
This would look something like:

#include <config.h>
#include "gansidecl.h"

#ifdef __STDC__
#include <stddef.h>
#else
#define size_t unsigned long
#endif

#ifndef HAVE_BCOPY
#undef bcopy
void
bcopy (src, dest, len)
  register char *src, *dest;
  int len;
{
  if (dest < src)
    while (len--)
      *dest++ = *src++;
  else
    {
      char *lasts = src + (len-1);
      char *lastd = dest + (len-1);
      while (len--)
        *(char *)lastd-- = *(char *)lasts--;
    }
}
#enidf /* !HAVE_BCOPY */

#ifdef HAVE_MEMCPY
PTR
memcpy (out, in, length)
     PTR out;
     CONST PTR in;
     size_t length;
{
    bcopy(in, out, length);
    return out;
}
#endef /* ! HAVE_MEMCPY */

#ifdef HAVE_MEMMOVE
PTR
memmove (s1, s2, n)
     PTR s1;
     CONST PTR s2;
     size_t n;
{
  bcopy (s2, s1, n);
  return s1;
}
#endif /* !HAVE_MEMMOVE */

There are some issues I'm not sure about:

1) Do we need to add prototypes for bcopy, memmove and/or memcpy
to some header file, if they are "missing"?

I don't see any necessity, or reason why it would be desirable,
but may be missing something.

2) Is there a problem with build vs host?  Is is the difference
between auto-host.h and auto-config.h?  I'm not clear on how
this happens;  perhaps we may need to compile string.c twice,
once for build and once for host.

Comments?  This suituation has been bugging for a long time, and
I think it is time to fix it.

	--Per Bothner
Cygnus Solutions     bothner@cygnus.com     http://www.cygnus.com/~bothner