ntpd: add optional support for /etc/ntp.conf

function                                             old     new   delta
add_peers                                              -      98     +98
packed_usage                                       29470   29511     +41
ntp_init                                             407     428     +21
pw_encrypt                                            14      27     +13
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(add/remove: 1/0 grow/shrink: 3/0 up/down: 173/0)             Total: 173 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
avoid calling bb_strtou twice in MIN macro expansion

Also, the maximum allowable value of swap priority is technically SWAP_FLAG_PRIO_MASK >> SWAP_FLAG_PRIO_SHIFT.

Signed-off-by: Matt Whitlock <busybox@mattwhitlock.name>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
fix interaction of -a and -p options in swapon

Swap entries in /etc/fstab inherit the priority specified on the command line unless they have 'pri' in their mount options.

Signed-off-by: Matt Whitlock <busybox@mattwhitlock.name>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
add discard option -d to swapon

Signed-off-by: Matt Whitlock <busybox@mattwhitlock.name>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>