./pcap-linux.c: In function 'pcap_cleanup_linux':
./pcap-linux.c:1090:15: error: storage size of 'ifr' isn't known
./pcap-linux.c: In function 'scan_sys_class_net':
./pcap-linux.c:1957:15: error: storage size of 'ifrflags' isn't known
./pcap-linux.c: In function 'scan_proc_net_dev':
etc.
this is referring to the struct ifreq, which at least in musl is defined in net/if.h
i'm uncertain whether it has to be there, as POSIX spec says nothing about this struct.
at the very least, configure should check for which header has the definition of that struct.
Administrators of the "libpcap" SourceForge project have superseded this tracker item (formerly artifact 3565780, now bug 171) with issue 174 of the "libpcap" GitHub project.