board/common: enable CONFIG_FEATURE_CHECK_NAMES for usernames

This commit enables a basic sanity check of usernames in BusyBox that by
default is disabled (!).  The rules enabled by this are:

 - the user or group name should consist only of letters, digits,
   underscores, periods, and dashes¹, and not start with a dash (as
   defined by IEEE Std 1003.1-2001), or periods²

 - for compatibility with Samba machine accounts, $ is supported at the
   end of names

 - max length of user or group name is 256 chars

Changes in this commit also includes a sync with latest BusyBox 1.36,
which adds: tree, tsort, SHA hw acceleration, and a separate script
for udhcpc6.

_____
¹) The documentation actually mentions "and at-signs" as well, but that
   has been explicitly removed from the source code.
²) The documentation does not mention that leading periods are not
   allowed, though this is also explicitly mentioned in the source code.

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

board/common/busybox_defconfig

@@ -1,7 +1,7 @@
 #
 # Automatically generated make config: don't edit
-# Busybox version: 1.35.0
-# Mon Dec 12 13:47:01 2022
+# Busybox version: 1.36.0
+# Fri Jul  7 17:59:34 2023
 #
 CONFIG_HAVE_DOT_CONFIG=y
 
@@ -93,6 +93,9 @@ CONFIG_FEATURE_BUFFERS_USE_MALLOC=y
 # CONFIG_FEATURE_BUFFERS_GO_IN_BSS is not set
 CONFIG_PASSWORD_MINLEN=6
 CONFIG_MD5_SMALL=1
+CONFIG_SHA1_SMALL=3
+CONFIG_SHA1_HWACCEL=y
+CONFIG_SHA256_HWACCEL=y
 CONFIG_SHA3_SMALL=1
 CONFIG_FEATURE_NON_POSIX_CP=y
 # CONFIG_FEATURE_VERBOSE_CP_MESSAGE is not set
@@ -123,6 +126,9 @@ CONFIG_LAST_SUPPORTED_WCHAR=0
 # CONFIG_UNICODE_BIDI_SUPPORT is not set
 # CONFIG_UNICODE_NEUTRAL_TABLE is not set
 # CONFIG_UNICODE_PRESERVE_BROKEN is not set
+# CONFIG_LOOP_CONFIGURE is not set
+# CONFIG_NO_LOOP_CONFIGURE is not set
+CONFIG_TRY_LOOP_CONFIGURE=y
 
 #
 # Applets
@@ -338,6 +344,7 @@ CONFIG_FEATURE_TR_CLASSES=y
 CONFIG_FEATURE_TR_EQUIV=y
 CONFIG_TRUE=y
 CONFIG_TRUNCATE=y
+CONFIG_TSORT=y
 CONFIG_TTY=y
 CONFIG_UNAME=y
 CONFIG_UNAME_OSNAME="GNU/Linux"
@@ -526,13 +533,13 @@ CONFIG_USE_BB_CRYPT_SHA=y
 CONFIG_ADDGROUP=y
 CONFIG_FEATURE_ADDUSER_TO_GROUP=y
 CONFIG_ADDUSER=y
-# CONFIG_FEATURE_CHECK_NAMES is not set
+CONFIG_FEATURE_CHECK_NAMES=y
 CONFIG_LAST_ID=60000
 CONFIG_FIRST_SYSTEM_ID=100
 CONFIG_LAST_SYSTEM_ID=999
 # CONFIG_CHPASSWD is not set
 CONFIG_FEATURE_DEFAULT_PASSWD_ALGO="md5"
-# CONFIG_CRYPTPW is not set
+CONFIG_CRYPTPW=y
 CONFIG_MKPASSWD=y
 CONFIG_DELUSER=y
 CONFIG_DELGROUP=y
@@ -831,10 +838,12 @@ CONFIG_READAHEAD=y
 CONFIG_RFKILL=y
 CONFIG_RUNLEVEL=y
 CONFIG_RX=y
+CONFIG_SEEDRNG=y
 CONFIG_SETFATTR=y
 CONFIG_SETSERIAL=y
 CONFIG_STRINGS=y
 CONFIG_TIME=y
+CONFIG_TREE=y
 CONFIG_TS=y
 CONFIG_TTYSIZE=y
 CONFIG_UBIATTACH=y
@@ -1007,6 +1016,7 @@ CONFIG_UDHCPC=y
 CONFIG_FEATURE_UDHCPC_ARPING=y
 CONFIG_FEATURE_UDHCPC_SANITIZEOPT=y
 CONFIG_UDHCPC_DEFAULT_SCRIPT="/usr/share/udhcpc/default.script"
+CONFIG_UDHCPC6_DEFAULT_SCRIPT="/usr/share/udhcpc/default6.script"
 CONFIG_UDHCPC6=y
 CONFIG_FEATURE_UDHCPC6_RFC3646=y
 CONFIG_FEATURE_UDHCPC6_RFC4704=y
@@ -1141,6 +1151,7 @@ CONFIG_ASH_IDLE_TIMEOUT=y
 CONFIG_ASH_ECHO=y
 CONFIG_ASH_PRINTF=y
 CONFIG_ASH_TEST=y
+CONFIG_ASH_SLEEP=y
 CONFIG_ASH_HELP=y
 CONFIG_ASH_GETOPTS=y
 CONFIG_ASH_CMDCMD=y