refactored alias.c heavily especially substituted the loop-based alias_expand() with a recursive approach. Now alias_expand() wraps alias_one() which recursively expands aliases. In principle the ``data processing'' is the same but now it's clearer structured and thus easier to understand IMO. The loop might have been faster but I don't care for speed -- the most simple solution is the best. It's fast enough, that is sufficient.

#undef DEF_MAIL_GROUP
#undef DEF_MAIL_USER

/* Define if you want to use lockfile library.  */
#undef USE_LIBLOCKFILE

#undef ENABLE_DEBUG

#undef ENABLE_RESOLVER

#undef ENABLE_AUTH

#undef USE_LIB_CRYPTO

#undef ENABLE_IDENT

#undef CONF_DIR

#undef DATA_DIR

#undef SBINDIR