当我通过 sudo apt-get install libnet1 安装 libnet 时，程序找不到 libnet.h，我也无法在 /usr/local/include 或 /usr/include 找到它。所以我下载了libnet并制作它，但我得到了错误
make -C lib/ lib
make[1]: Entering director `/home/liuqiang/workspace/libnet/lib'
gcc -O2 -Wall -Werror -Wno-unused -Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations -g -I../include -Iinclude -DTARGET_LINUX -c -o core/config.o core/config.c
cc1: warnings being treated as errors
core/config.c: In function ‘__libnet_internal__seek_section’:
core/config.c:87: error: ignoring return value of ‘fgets’, declared with attribute warn_unused_result
core/config.c: In function ‘__libnet_internal__get_setting’:
core/config.c:111: error: ignoring return value of ‘fgets’, declared with attribute warn_unused_result
make[1]: *** [core/config.o] error 1
make[1]:Leaving directory `/home/liuqiang/workspace/libnet/lib'
make: *** [lib] error 2