malloc.3: Replace discussion of MALLOC_CHECK_ with pointer to mallopt(3)

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man3/malloc.3

@@ -25,7 +25,7 @@
 .\" Documented MALLOC_CHECK_, Wolfram Gloger (wmglo@dent.med.uni-muenchen.de)
 .\" 2007-09-15 mtk: added notes on malloc()'s use of sbrk() and mmap().
 .\"
-.TH MALLOC 3  2012-03-09 "GNU" "Linux Programmer's Manual"
+.TH MALLOC 3  2012-03-20 "GNU" "Linux Programmer's Manual"
 .SH NAME
 malloc, free, calloc, realloc \- Allocate and free dynamic memory
 .SH SYNOPSIS
@@ -253,30 +253,8 @@ Recent versions of Linux libc (later than 5.4.23) and glibc (2.x)
 include a
 .BR malloc ()
 implementation which is tunable via environment variables.
-When
-.B MALLOC_CHECK_
-is set, a special (less efficient) implementation is used which
-is designed to be tolerant against simple errors, such as double
-calls of
-.BR free ()
-with the same argument, or overruns of a single byte (off-by-one
-bugs).
-Not all such errors can be protected against, however, and
-memory leaks can result.
-If
-.B MALLOC_CHECK_
-is set to 0, any detected heap corruption is silently ignored;
-if set to 1, a diagnostic message is printed on \fIstderr\fP;
-if set to 2,
-.BR abort (3)
-is called immediately;
-if set to 3, a diagnostic message is printed on \fIstderr\fP
-and the program is aborted.
-Using a nonzero
-.B MALLOC_CHECK_
-value can be useful because otherwise
-a crash may happen much later, and the true cause for the problem
-is then very hard to track down.
+For details, see
+.BR mallopt (3).
 .SH "SEE ALSO"
 .\" http://g.oswego.edu/dl/html/malloc.html
 .\" A Memory Allocator - by Doug Lea 
@@ -289,8 +267,8 @@ is then very hard to track down.
 .\"     Check Lever, David Boreham
 .\" 
 .BR brk (2),
-.\" .BR mallopt (3),
 .BR mmap (2),
 .BR alloca (3),
+.BR mallopt (3),
 .BR mtrace (3),
 .BR posix_memalign (3)