I do have libpcap-devel installed, it's just this pcap-int.h header that 
is both missing and not to be found in any Fedora package: 

$ rpm -qa | grep pcap-dev 
libpcap-devel-1.6.2-1.fc21.x86_64 

Note the following tickets: 

https://bugzilla.redhat.com/show_bug.cgi?id=449387 
https://code.google.com/p/pypcap/issues/detail?id=45 

It looks like this wasn't included on purpose - pypcap is using 
libpcap's private interface. Note that according to Google Code, this 
package had no releases or SVN updates since 2010.