ptmalloc is the original version of the malloc that was later included
in GNU libc.  This version is also but *not* exclusively LGPL:

  Copyright (c) 2001-2006 Wolfram Gloger
  
  Permission to use, copy, modify, distribute, and sell this software
  and its documentation for any purpose is hereby granted without fee,
  provided that (i) the above copyright notices and this permission
  notice appear in all copies of the software and related
  documentation, and (ii) the name of Wolfram Gloger may not be used
  in any advertising or publicity relating to the software.
  
  THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
  EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
  WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
  
  IN NO EVENT SHALL WOLFRAM GLOGER BE LIABLE FOR ANY SPECIAL,
  INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND, OR ANY
  DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
  WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY
  THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  PERFORMANCE OF THIS SOFTWARE.

This package comes with no documentation beyond a README, which isn't
worth installing.  It appears that the GNU libc man page malloc(3)
applies, but it's not included here for copyright reasons.

WWW: http://www.malloc.de/en/