board/common: optimize busybox for speed, drop fork+exec for applets

- The biggest changes are syncing with latest BusyBox (busybox-update-config)
 - Disable optimize for size
 - Enable feature "SH_NOFORK" which allows /bin/sh to call applet_main()
   directly without having to fork+exec busybox

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: 1.36.1
-# Sun Feb  9 12:25:37 2025
+# Busybox version: 1.37.0
+# Mon Feb  9 07:51:08 2026
 #
 CONFIG_HAVE_DOT_CONFIG=y
 
@@ -17,6 +17,7 @@ CONFIG_SHOW_USAGE=y
 CONFIG_FEATURE_VERBOSE_USAGE=y
 # CONFIG_FEATURE_COMPRESS_USAGE is not set
 CONFIG_LFS=y
+CONFIG_TIME64=y
 CONFIG_PAM=y
 CONFIG_FEATURE_DEVPTS=y
 CONFIG_FEATURE_UTMP=y
@@ -469,6 +470,7 @@ CONFIG_FEATURE_FIND_NEWER=y
 CONFIG_FEATURE_FIND_SAMEFILE=y
 CONFIG_FEATURE_FIND_EXEC=y
 CONFIG_FEATURE_FIND_EXEC_PLUS=y
+CONFIG_FEATURE_FIND_EXEC_OK=y
 CONFIG_FEATURE_FIND_USER=y
 CONFIG_FEATURE_FIND_GROUP=y
 CONFIG_FEATURE_FIND_NOT=y
@@ -795,6 +797,7 @@ CONFIG_FLASH_ERASEALL=y
 CONFIG_FLASH_LOCK=y
 CONFIG_FLASH_UNLOCK=y
 CONFIG_FLASHCP=y
+CONFIG_GETFATTR=y
 CONFIG_HDPARM=y
 CONFIG_FEATURE_HDPARM_GET_IDENTITY=y
 # CONFIG_FEATURE_HDPARM_HDIO_SCAN_HWIF is not set
@@ -933,6 +936,7 @@ CONFIG_IPRULE=y
 CONFIG_IPNEIGH=y
 CONFIG_FEATURE_IP_ADDRESS=y
 CONFIG_FEATURE_IP_LINK=y
+CONFIG_FEATURE_IP_LINK_CAN=y
 CONFIG_FEATURE_IP_ROUTE=y
 CONFIG_FEATURE_IP_ROUTE_DIR="/etc/iproute2"
 CONFIG_FEATURE_IP_TUNNEL=y
@@ -1007,6 +1011,7 @@ CONFIG_FEATURE_WGET_HTTPS=y
 CONFIG_WHOIS=y
 CONFIG_ZCIP=y
 CONFIG_UDHCPD=y
+CONFIG_FEATURE_UDHCPD_BOOTP=y
 CONFIG_FEATURE_UDHCPD_BASE_IP_ON_MAC=y
 CONFIG_FEATURE_UDHCPD_WRITE_LEASES_EARLY=y
 CONFIG_DHCPD_LEASES_FILE="/var/lib/misc/udhcpd.leases"
@@ -1016,7 +1021,12 @@ 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=""
 # CONFIG_UDHCPC6 is not set
+# CONFIG_FEATURE_UDHCPC6_RFC3646 is not set
+# CONFIG_FEATURE_UDHCPC6_RFC4704 is not set
+# CONFIG_FEATURE_UDHCPC6_RFC4833 is not set
+# CONFIG_FEATURE_UDHCPC6_RFC5970 is not set
 
 #
 # Common options for DHCP applets
@@ -1027,7 +1037,7 @@ CONFIG_UDHCP_DEBUG=0
 CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS=80
 CONFIG_FEATURE_UDHCP_RFC3397=y
 CONFIG_FEATURE_UDHCP_8021Q=y
-CONFIG_IFUPDOWN_UDHCPC_CMD_OPTIONS="-b -R -n -O search"
+CONFIG_IFUPDOWN_UDHCPC_CMD_OPTIONS=""
 
 #
 # Print Utilities
@@ -1132,7 +1142,7 @@ CONFIG_SH_IS_ASH=y
 CONFIG_BASH_IS_NONE=y
 CONFIG_SHELL_ASH=y
 CONFIG_ASH=y
-CONFIG_ASH_OPTIMIZE_FOR_SIZE=y
+# CONFIG_ASH_OPTIMIZE_FOR_SIZE is not set
 CONFIG_ASH_INTERNAL_GLOB=y
 CONFIG_ASH_BASH_COMPAT=y
 # CONFIG_ASH_BASH_SOURCE_CURDIR is not set
@@ -1146,7 +1156,6 @@ 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
@@ -1197,7 +1206,7 @@ CONFIG_FEATURE_SH_MATH_64=y
 CONFIG_FEATURE_SH_MATH_BASE=y
 CONFIG_FEATURE_SH_EXTRA_QUIET=y
 # CONFIG_FEATURE_SH_STANDALONE is not set
-# CONFIG_FEATURE_SH_NOFORK is not set
+CONFIG_FEATURE_SH_NOFORK=y
 CONFIG_FEATURE_SH_READ_FRAC=y
 # CONFIG_FEATURE_SH_HISTFILESIZE is not set
 CONFIG_FEATURE_SH_EMBEDDED_SCRIPTS=y