[Bro] building bro w/ dynamic libpcap?

[Bond Masuda]

Hello,

Trying to build bro with pf_ring's libpcap, but the 'configure' script 
seems to choose static libpcap.a over libpcap.so:

$ ./configure --with-pcap=/usr/local
Build Directory : build
Source Directory: /home/bmasuda/RPMBUILD/BUILD/bro-2.4.1
-- Found sed: /usr/bin/sed
-- Found Perl: /usr/bin/perl (found version "5.16.3")
-- Found FLEX: 2.5.37
-- Found BISON: /usr/bin/bison
-- Found PCAP: /usr/local/lib/libpcap.a

pf_ring is installed in /usr/local/lib:

$ ls -l /usr/local/lib
total 3536
drwxr-xr-x. 2 root root      96 Mar  3 07:35 daq
-rw-r--r--. 1 root root  461618 Mar  2 21:13 libpcap.a
lrwxrwxrwx. 1 root root      16 Mar  3 07:35 libpcap.so.1 -> 
libpcap.so.1.7.4
-rwxr-xr-x. 1 root root 1452912 Mar  2 21:13 libpcap.so.1.7.4
-rw-r--r--. 1 root root  692966 Mar  2 21:13 libpfring.a
-rwxr-xr-x. 1 root root  517664 Mar  2 21:13 libpfring.so
lrwxrwxrwx. 1 root root      17 Mar  3 07:35 libsfbpf.so.0 -> 
libsfbpf.so.0.0.1
-rwxrwxr-x. 1 root root  486933 Oct 10  2015 libsfbpf.so.0.0.1

I would like for bro to be linked dynamically with the libpcap.so 
instead of libpcap.a. How can I specify this?

Above example is with bro 2.4.1, but same thing with 2.5 as well.

Thanks,
Bond