Updated the trunk to latest, see that -lrt is added to the Makefile, but still having the same error. Already tried make clean hostapd-wpad-min.
CFLAGS="-I/home/terence/openwrt/openwrt/staging_dir/target-mips_34kc_eglibc-2.15/usr/include/libnl-tiny -I/home/terence/openwrt/openwrt/build_dir/target-mips_34kc_eglibc-2.15/hostap
d-wpad-mini/hostapd-20131120/src/crypto -I/home/terence/openwrt/openwrt/staging_dir/target-mips_34kc_eglibc-2.15/usr/include -I/home/terence/openwrt/openwrt/staging_dir/target-mips_
34kc_eglibc-2.15/include -I/home/terence/openwrt/openwrt/staging_dir/toolchain-mips_34kc_gcc-4.6-linaro_eglibc-2.15/usr/include -I/home/terence/openwrt/openwrt/staging_dir/toolchain
-mips_34kc_gcc-4.6-linaro_eglibc-2.15/include -I/home/terence/openwrt/openwrt/package/network/services/hostapd/madwifi -DCONFIG_LIBNL20 -D_GNU_SOURCE -DCONFIG_MSG_MIN_PRIORITY=3 -Os
-pipe -mno-branch-likely -mips32r2 -mtune=34kc -fno-caller-saves -fhonour-copts -Wno-error=unused-but-set-variable -msoft-float -ffunction-sections -fdata-sections" make -C /home
/terence/openwrt/openwrt/build_dir/target-mips_34kc_eglibc-2.15/hostapd-wpad-mini/hostapd-20131120/hostapd AR=mips-openwrt-linux-gnu-ar AS="mips-openwrt-linux-gnu-gcc -c -Os -pipe -
mno-branch-likely -mips32r2 -mtune=34kc -fno-caller-saves -fhonour-copts -Wno-error=unused-but-set-variable -msoft-float -ffunction-sections -fdata-sections" LD=mips-openwrt-linux-g
nu-ld NM=mips-openwrt-linux-gnu-nm CC="mips-openwrt-linux-gnu-gcc" GCC="mips-openwrt-linux-gnu-gcc" CXX="mips-openwrt-linux-gnu-g++" RANLIB=mips-openwrt-linux-gnu-ranlib STRIP=mips-
openwrt-linux-gnu-strip OBJCOPY=mips-openwrt-linux-gnu-objcopy OBJDUMP=mips-openwrt-linux-gnu-objdump SIZE=mips-openwrt-linux-gnu-size CONFIG_DRIVER_NL80211=y CONFIG_DRIVER_MADWIFI=
CONFIG_DRIVER_HOSTAP= CONFIG_IEEE80211N=y CONFIG_IEEE80211W=y CONFIG_DRIVER_WEXT= CONFIG_DRIVER_ROBOSWITCH= LIBS="-L/home/terence/openwrt/openwrt/staging_dir/target-mips_34kc_egli
bc-2.15/usr/lib -L/home/terence/openwrt/openwrt/staging_dir/target-mips_34kc_eglibc-2.15/lib -L/home/terence/openwrt/openwrt/staging_dir/toolchain-mips_34kc_gcc-4.6-linaro_eglibc-2.
15/usr/lib -L/home/terence/openwrt/openwrt/staging_dir/toolchain-mips_34kc_gcc-4.6-linaro_eglibc-2.15/lib -lrt -Wl,--gc-sections -lubox -lubus -lm -lnl-tiny" LIBS_c="" BCHECK= CFLA
GS="$(cat /home/terence/openwrt/openwrt/build_dir/target-mips_34kc_eglibc-2.15/hostapd-wpad-mini/hostapd-20131120/.cflags)" MULTICALL=1 hostapd_cli hostapd_multi.a
make[4]: Entering directory '/home/terence/openwrt/openwrt/build_dir/target-mips_34kc_eglibc-2.15/hostapd-wpad-mini/hostapd-20131120/hostapd'
CC hostapd_cli.c
CC ../src/common/wpa_ctrl.c
CC ../src/utils/os_unix.c
CC ../src/utils/eloop.c
CC ../src/utils/wpa_debug.c
CC ../src/utils/edit_simple.c
../src/utils/os_unix.o: In function `os_get_reltime':
os_unix.c:(.text.os_get_reltime+0x3c): undefined reference to `clock_gettime'
collect2: ld returned 1 exit status
Makefile:920: recipe for target 'hostapd_cli' failed
librt seems to be there.
./build_dir/target-mips_34kc_eglibc-2.15/toolchain/ipkg-ar71xx/librt
./build_dir/target-mips_34kc_eglibc-2.15/toolchain/ipkg-ar71xx/librt/lib/librt-2.15.so
./build_dir/target-mips_34kc_eglibc-2.15/toolchain/ipkg-ar71xx/librt/lib/librt.so.1
./build_dir/toolchain-mips_34kc_gcc-4.6-linaro_eglibc-2.15/eglibc-2.15-r18909-headers/librt.map
./build_dir/toolchain-mips_34kc_gcc-4.6-linaro_eglibc-2.15/eglibc-2.15-r18909/libc/abilist/librt.abilist
./build_dir/toolchain-mips_34kc_gcc-4.6-linaro_eglibc-2.15/eglibc-2.15-r18909/libc/nptl/sysdeps/pthread/librt-cancellation.c
./build_dir/toolchain-mips_34kc_gcc-4.6-linaro_eglibc-2.15/eglibc-2.15-r18909/libc/nptl/sysdeps/unix/sysv/linux/x86_64/librt-cancellation.S
./build_dir/toolchain-mips_34kc_gcc-4.6-linaro_eglibc-2.15/eglibc-2.15-r18909-final/rt/librt-cancellation.os.d
./build_dir/toolchain-mips_34kc_gcc-4.6-linaro_eglibc-2.15/eglibc-2.15-r18909-final/rt/librt_pic.a
./build_dir/toolchain-mips_34kc_gcc-4.6-linaro_eglibc-2.15/eglibc-2.15-r18909-final/rt/librt-cancellation.os
./build_dir/toolchain-mips_34kc_gcc-4.6-linaro_eglibc-2.15/eglibc-2.15-r18909-final/rt/librt-cancellation.o.d
./build_dir/toolchain-mips_34kc_gcc-4.6-linaro_eglibc-2.15/eglibc-2.15-r18909-final/rt/librt-cancellation.o
./build_dir/toolchain-mips_34kc_gcc-4.6-linaro_eglibc-2.15/eglibc-2.15-r18909-final/rt/librt.a
./build_dir/toolchain-mips_34kc_gcc-4.6-linaro_eglibc-2.15/eglibc-2.15-r18909-final/rt/librt.so
./build_dir/toolchain-mips_34kc_gcc-4.6-linaro_eglibc-2.15/eglibc-2.15-r18909-final/rt/librt.so.1
./build_dir/toolchain-mips_34kc_gcc-4.6-linaro_eglibc-2.15/eglibc-2.15-r18909-final/librt.map
./build_dir/toolchain-mips_34kc_gcc-4.6-linaro_eglibc-2.15/eglibc-2.15-r18909-final/elf/librtld.os.map
./build_dir/toolchain-mips_34kc_gcc-4.6-linaro_eglibc-2.15/eglibc-2.15-r18909-final/elf/librtld.mk
./build_dir/toolchain-mips_34kc_gcc-4.6-linaro_eglibc-2.15/eglibc-2.15-r18909-final/elf/librtld.map
./build_dir/toolchain-mips_34kc_gcc-4.6-linaro_eglibc-2.15/eglibc-2.15-r18909-final/elf/librtld.os
./staging_dir/target-mips_34kc_eglibc-2.15/pkginfo/librt.provides
./staging_dir/target-mips_34kc_eglibc-2.15/root-ar71xx/lib/librt_pic.a
./staging_dir/target-mips_34kc_eglibc-2.15/root-ar71xx/lib/librt-2.15.so
./staging_dir/target-mips_34kc_eglibc-2.15/root-ar71xx/lib/librt.a
./staging_dir/target-mips_34kc_eglibc-2.15/root-ar71xx/lib/librt.so.1
./staging_dir/toolchain-mips_34kc_gcc-4.6-linaro_eglibc-2.15/lib/librt_pic.a
./staging_dir/toolchain-mips_34kc_gcc-4.6-linaro_eglibc-2.15/lib/librt-2.15.so
./staging_dir/toolchain-mips_34kc_gcc-4.6-linaro_eglibc-2.15/lib/librt_pic.map
./staging_dir/toolchain-mips_34kc_gcc-4.6-linaro_eglibc-2.15/lib/librt.a
./staging_dir/toolchain-mips_34kc_gcc-4.6-linaro_eglibc-2.15/lib/librt.so
./staging_dir/toolchain-mips_34kc_gcc-4.6-linaro_eglibc-2.15/lib/librt.so.1