Remove now-unnecessary direct stdlib.h #includes.

Removed all invocations of strtoll() and friends.

auth: Refuse to run checkpassword script insecurely by default

Renamed str_tabescape_write() to str_append_tabescaped()

checkpassword: Escape transferred extra fields properly.

auth: checkpassword code cleanup. Also fixed some error handling. Removes a lot of copy&pasted code between passdb and userdb.

Added missing changes to userdb checkpassword. --HG-- branch : HEAD

checkpassword: Allow setting uid/gid in userdb_uid and userdb_gid environment. --HG-- branch : HEAD

If USER environment is set, return it in "user" field and not "userdb_user". Also don't require that the USER environment exists. --HG-- branch : HEAD

Don't crash if USER or HOME environment is missing. Allow HOME environment not to exist. --HG-- branch : HEAD

Allow checkpassword program to send extra parameters to Dovecot. EXTRA environment contains a list of environment variables that are passed to Dovecot. --HG-- branch : HEAD

userdb = passdb works now with checkpassword passdb. --HG-- branch : HEAD

Added checkpassword passdb. userdb has only beginnings. --HG-- branch : HEAD