sysctl: do not error out showing write-only data. Closes 6386

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
libbb: trivial code shrink

function                                             old     new   delta
reset_ino_dev_hashtable                               84      74     -10

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
du, copy_file: fix file matching on cramfs. Closes 5456

function                                             old     new   delta
is_in_ino_dev_hashtable                               88     108     +20
add_to_ino_dev_hashtable                             150     142      -8
reset_ino_dev_hashtable                               84      75      -9
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/2 up/down: 20/-17)              Total: 3 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
build system: remove a dead link from Config help text

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
hwclock: fix setting of tz_minuteswest. Closes 5414

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>