configure: add support for libdir and prefix option

index 7f4f3bd9..d57ce0f8 100755
@@ -501,18 +501,30 @@ if [ $# -eq 1 ] && [ "$(echo $1 | cut -c 1)" != '-' ]; then
 else
 	while true; do
 		case "$1" in
-			--include_dir)
-				INCLUDE=$2
-				shift 2 ;;
-			--libbpf_dir)
-				LIBBPF_DIR="$2"
-				shift 2 ;;
-			--libbpf_force)
-				if [ "$2" != 'on' ] && [ "$2" != 'off' ]; then
+			--include_dir | --include_dir=*)
+				INCLUDE="${1#*=}"
+				if [ "$INCLUDE" == "--include_dir" ]; then
+					INCLUDE=$2
+					shift
+				fi
+				shift ;;
+			--libbpf_dir | --libbpf_dir=*)
+				LIBBPF_DIR="${1#*=}"
+				if [ "$LIBBPF_DIR" == "--libbpf_dir" ]; then
+					LIBBPF_DIR="$2"
+					shift
+				fi
+				shift ;;
+			--libbpf_force | --libbpf_force=*)
+				LIBBPF_FORCE="${1#*=}"
+				if [ "$LIBBPF_FORCE" == "--libbpf_force" ]; then
+					LIBBPF_FORCE="$2"
+					shift
+				fi
+				if [ "$LIBBPF_FORCE" != 'on' ] && [ "$LIBBPF_FORCE" != 'off' ]; then
 					usage 1
 				fi
-				LIBBPF_FORCE=$2
-				shift 2 ;;
+				shift ;;
 			-h | --help)
 				usage 0 ;;
 			"")

index d57ce0f8..8be7e40b 100755
@@ -148,6 +148,15 @@ EOF
 	rm -f $TMPDIR/ipttest.c $TMPDIR/ipttest
 }
 
+check_prefix()
+{
+	if [ -n "$PREFIX" ]; then
+		prefix="$PREFIX"
+	else
+		prefix="/usr"
+	fi
+}
+
 check_ipt()
 {
 	if ! grep TC_CONFIG_XT $CONFIG > /dev/null; then

@@ -490,6 +499,7 @@ Usage: $0 [OPTIONS]
 	--libbpf_force		Enable/disable libbpf by force. Available options:
 				  on: require link against libbpf, quit config if no libbpf support
 				  off: disable libbpf probing
+	--prefix		Path prefix of the lib files to install
 	-h | --help		Show this usage info
 EOF
 	exit $1

@@ -525,6 +535,13 @@ else
 					usage 1
 				fi
 				shift ;;
+			--prefix | --prefix=*)
+				PREFIX="${1#*=}"
+				if [ "$PREFIX" == "--prefix" ]; then
+					PREFIX="$2"
+					shift
+				fi
+				shift ;;
 			-h | --help)
 				usage 0 ;;
 			"")

@@ -558,6 +575,7 @@ if ! grep -q TC_CONFIG_NO_XT $CONFIG; then
 fi
 
 echo
+check_prefix
 if ! grep -q TC_CONFIG_NO_XT $CONFIG; then
 	echo -n "iptables modules directory: "
 	check_ipt_lib_dir

index 5bc11477..45655ca4 100644
@@ -1,6 +1,8 @@
 # SPDX-License-Identifier: GPL-2.0
 # Top level Makefile for iproute2
 
+-include config.mk
+
 ifeq ("$(origin V)", "command line")
 VERBOSE = $(V)
 endif

@@ -13,7 +15,6 @@ MAKEFLAGS += --no-print-directory
 endif
 
 PREFIX?=/usr
-LIBDIR?=$(PREFIX)/lib
 SBINDIR?=/sbin
 CONFDIR?=/etc/iproute2
 NETNS_RUN_DIR?=/var/run/netns

@@ -60,7 +61,7 @@ SUBDIRS=lib ip tc bridge misc netem genl tipc devlink rdma dcb man vdpa
 LIBNETLINK=../lib/libutil.a ../lib/libnetlink.a
 LDLIBS += $(LIBNETLINK)
 
-all: config
+all: config.mk
 	@set -e; \
 	for i in $(SUBDIRS); \
 	do echo; echo $$i; $(MAKE) -C $$i; done

@@ -80,7 +81,7 @@ help:
 	@echo "Make Arguments:"
 	@echo " V=[0|1]             - set build verbosity level"
 
-config:
+config.mk:
 	@if [ ! -f config.mk -o configure -nt config.mk ]; then \
 		sh configure $(KERNEL_INCLUDE); \
 	fi

index 8be7e40b..858d2e41 100755
@@ -157,6 +157,19 @@ check_prefix()
 	fi
 }
 
+check_lib_dir()
+{
+	echo -n "lib directory: "
+	if [ -n "$LIBDIR" ]; then
+		eval echo "$LIBDIR"
+		eval echo "LIBDIR:=$LIBDIR" >> $CONFIG
+		return
+	fi
+
+	eval echo "${prefix}/lib"
+	eval echo "LIBDIR:=${prefix}/lib" >> $CONFIG
+}
+
 check_ipt()
 {
 	if ! grep TC_CONFIG_XT $CONFIG > /dev/null; then

@@ -495,6 +508,7 @@ usage()
 	cat <<EOF
 Usage: $0 [OPTIONS]
 	--include_dir		Path to iproute2 include dir
+	--libdir		Path to iproute2 lib dir
 	--libbpf_dir		Path to libbpf DESTDIR
 	--libbpf_force		Enable/disable libbpf by force. Available options:
 				  on: require link against libbpf, quit config if no libbpf support

@@ -518,6 +532,13 @@ else
 					shift
 				fi
 				shift ;;
+			--libdir | --libdir=*)
+				LIBDIR="${1#*=}"
+				if [ "$LIBDIR" == "--libdir" ]; then
+					LIBDIR="$2"
+					shift
+				fi
+				shift ;;
 			--libbpf_dir | --libbpf_dir=*)
 				LIBBPF_DIR="${1#*=}"
 				if [ "$LIBBPF_DIR" == "--libbpf_dir" ]; then

@@ -576,6 +597,7 @@ fi
 
 echo
 check_prefix
+check_lib_dir
 if ! grep -q TC_CONFIG_NO_XT $CONFIG; then
 	echo -n "iptables modules directory: "
 	check_ipt_lib_dir