softlimit: Add support for reading limits from env vars
softlimit: Add support for reading limits from env vars

The environment variables are:

-a	$SOFTLIMIT_ALLBYTES
-c	$SOFTLIMIT_COREBYTES
-d	$SOFTLIMIT_DATABYTES
-f	$SOFTLIMIT_FILEBYTES
-l	$SOFTLIMIT_LOCKEDBYTES
-m	$SOFTLIMIT_MEMBYTES
-o	$SOFTLIMIT_OPENFILES
-p	$SOFTLIMIT_PROCS
-r	$SOFTLIMIT_RSSBYTES
-s	$SOFTLIMIT_STACKBYTES
-t	$SOFTLIMIT_CPUSECS

bruceg/daemontools-encore,bruceg/daemontools-encore,bruceg/daemontools-encore