Update to 0.22.0

  Improvements in cross-compilation. The following variables were
    introduced: TOOLDIR, SYSROOT, TOOLCHAIN_PREFIX and
    MACHINE_GNU_PLATFORM.

  PROGS variable was introduced (sf.net bug #3445658).

  Support for Lua submodules was added (e.g. net.socket.lua ->
  net/socket.lua). New variable LUA_MODULES was introduced for this
  purpose.

  MKPIE (Position Independent Executables), USE_SSP (Stack Smashing
  Protection), USE_FORT and USE_RELRO variables were introduced for
  security reasons.

  Variable OBJDIR_<dir> was introduced.

  mkc.subdir.mk and mkc.subprj.mk: Commands associated with targets
  "all", "install", "clean", "cleandir", "depend", "test",
  "installdirs", "uninstall", "errorcheck" and "filelist" in Makefile
  override the standard behaviour.

  MKC_REQUIRE_HEADERS, MKC_REQUIRE_DEFINES, MKC_REQUIRE_TYPES,
  MKC_REQUIRE_VARS, MKC_REQUIRE_MEMBERS, MKC_REQUIRE_FUNCS<n> and
  MKC_REQUIRE_CUSTOM do not change CFLAGS.

  mkc.subdir.mk and mkc.subprj.mk: "cleandir" target takes into
  account CLEANFILES, CLEANDIRS, DISTCLEANFILES and DISTCLEANDIRS
  variables (removes files).

  PCNAME.<lib> variable was introduced in mkc_imp.pkg-config.mk, this
  is a map from library name to pcname (.pc).

  Improvements for SHRTOUT.

  New variable OBJCOPY was introduced.

  Update of the presentation.

  Fix in manual page (sf.net bug #3441610).

  New regression tests (examples).

(cheusov)