Could NOT find PCAP (missing: PCAP_LIBRARIES PCAP_INCLUDE_DIRS)
在安装PCL时会有这样的错误：
Could NOT find PCAP (missing: PCAP_LIBRARIES PCAP_INCLUDE_DIRS)
1.下载pcap包，地址：http://www.tcpdump.org/#latest-release
$ tar -zxvf libpcap-1.9.0.tar.gz $ cd libpcap-1.9.0 $ ./configure $ make -j8 $ sudo make install
2.如果在./configure时出现：
configure: error: Neither flex nor lex was found.
解决办法：
$ sudo apt-get install flex bison
Done!