Update memory tracking/debugging reference

 after a complete session,

 memanalyze.pl is the perl script present only present in CVS (not part of the

 release archives) that analyzes a log file generated by the memdebug

 release archives) that analyzes a log file generated by the memory tracking

 system. It detects if resources are allocated but never freed and other kinds

 of errors related to resource management.

 Use -DMALLOCDEBUG when compiling to enable memory debugging, this is also

 switched on by running configure with --enable-debug.

 Internally, definition of preprocessor symbol DEBUGBUILD restricts code which

 is only compiled for debug enabled builds. And symbol CURLDEBUG is used to

 differentiate code which is _only_ used for memory tracking/debugging.

 Use -DCURLDEBUG when compiling to enable memory debugging, this is also

 switched on by running configure with --enable-curldebug. Use -DDEBUGBUILD

 when compiling to enable a debug build or run configure with --enable-debug.

 curl --version will list 'Debug' feature for debug enabled builds, and

 will list 'TrackMemory' feature for curl debug memory tracking capable

 builds. These features are independent and can be controlled when running

 the configure script. When --enable-debug is given both features will be

 enabled, unless some restriction prevents memory tracking from being used.

Test Suite

==========

#define BSD

/* #define MALLOCDEBUG */

/* CURLDEBUG definition enables memory tracking */

/* #define CURLDEBUG */

/* USE_ZLIB on cmd-line */

#ifdef USE_ZLIB