* make version-specific aliases for LUA_INIT, LUA_PATH, LUA_CPATH
* add Mike Pall's advanced readline support as a module
* consider using libedit in place of libreadline, as it's easier than
  explaining that our distribution of the "lua" interpreter is under the GPL.
* investigate use of versioned symbols in the .so.  This will allow e.g.
  debuggers that can support multiple Lua versions simultaneously, and
  apps which assemble components using different Lua versions.  (Hint:
  module .so's *must* be linked against the Lua library.)
* include soname number in source package name (on next increment).  May
  want to split library and command line tools into separate source packages.
* want way to avoid hard-coding package and path names in
  lua5.1.postinst, etc.