[root@localhost libpcap-0.8.1]# ./configure
loading cache ./config.cache
checking host system type... x86_64-unknown-linux-gnu
checking target system type... x86_64-unknown-linux-gnu
checking build system type... x86_64-unknown-linux-gnu
checking for gcc... gcc
checking whether the C compiler (gcc ) works... yes
checking whether the C compiler (gcc ) is a cross-compiler... no
checking whether we are using GNU C... yes
checking whether gcc accepts -g... yes
checking gcc version... 4
checking for inline... inline
checking for __attribute__... no
checking for u_int8_t using gcc... yes
checking for u_int16_t using gcc... yes
checking for u_int32_t using gcc... yes
checking how to run the C preprocessor... gcc -E
checking for sys/ioccom.h... no
checking for sys/sockio.h... no
checking for ifaddrs.h... yes
checking for limits.h... yes
checking for netinet/if_ether.h... yes
checking for ANSI ioctl definitions... yes
checking for ether_hostton... yes
checking for strerror... yes
checking for strlcpy... no
checking for vsnprintf... yes
checking for snprintf... yes
checking if --disable-protochain option is specified... enabled
checking packet capture type... linux
checking for getifaddrs... yes
checking if --enable-ipv6 option is specified... no
checking whether to build optimizer debugging code... no
checking whether to build parser debugging code... no
checking Linux kernel version... 2
checking if if_packet.h has tpacket_stats defined... yes
checking whether we have /proc/net/dev... yes
checking whether we have DAG API... no
checking for flex... no
checking for bison... no
checking for capable lex... insufficient
configure: error: Your operating system's lex is insufficient to compile
libpcap. flex is a lex replacement that has many advantages, including
being able to compile libpcap. For more information, see
http://www.gnu.org/software/flex/flex.html .

[root@localhost libpcap-0.8.1]# make
make: *** No targets specified and no makefile found. Stop.

А сейчас в чем проблема?