required autotools macro written and deployed in all apropriate Makefile.ams.
Use cases checked:
- linux, standard location of zlib, no ndb
- linux, standard locatoin of zlib, with ndb
- linux, non-standard location of zlib, no ndb
- hpux11, use of bundled zlib, no ndb 
The only non-checked case is non-standard location of zlib (or use of bundled
zlib) + ndb. I wasn't able to check it as ndb/ just won't compile on beasts 
like AIX52 or HPUX11, where such a check is possible. It didn't compile 
there before as these systems dont't have installed zlib, so nothing got broken ;)


Makefile.am:
  WL#1518 "make bundled zlib usable for unix builds", part 2:
  - zlib dir should be built only if there is no system zlib available;
    with introducing of DIST_SUBDIRS goal, os2, BUILD and SSH now only entered
    if make dist
acinclude.m4:
  WL#1518, "make bundled zlib usable for unix builds":
  - actual implementation of the check for various zlib usage options
configure.in:
  WL#1518, "make bundled zlib usable for unix builds":
  - MYSQL_CHECK_ZLIB_WITH_COMPRESS deployed
libmysql/Makefile.am:
  WL#1518, "make bundled zlib usable for unix builds":
  - support for non-standard zlib include dir added
libmysql_r/Makefile.am:
  WL#1518, "make bundled zlib usable for unix builds":
  - support for non-standard zlib include dir added
libmysqld/Makefile.am:
  WL#1518, "make bundled zlib usable for unix builds":
  - support for non-standard zlib include dir added
myisam/Makefile.am:
  WL#1518, "make bundled zlib usable for unix builds":
  - support for non-standard zlib binary dir added
mysys/Makefile.am:
  WL#1518, "make bundled zlib usable for unix builds":
  - support for non-standard zlib include dir added
sql/Makefile.am:
  WL#1518, "make bundled zlib usable for unix builds":
  - support for non-standard zlib include dir and library dir added
tools/Makefile.am:
  WL#1518, "make bundled zlib usable for unix builds":
  - support for non-standard zlib include dir added
  - copyright added