On a fresh VoidLinux, I compiled tcpdump source code and met following errors during configuration:
# ../configure CFLAGS='-g -O0'
......
checking for local pcap library... not found
checking for pkg-config... no
checking for pcap-config... no
checking for main in -lpcap... no
configure: error: see the INSTALL doc for more info
I was sure libpcap was already installed. After some investigating, I found the root cause was libpcap-devel was needed:
# xbps-install -Suv libpcap-devel
......
Then the issue was fixed.