link: require no space between `-L' and `/usr/lib64
grep -n "L /usr" Makefile
... The reply is : 1451:LIBPCAP_LIBS = -L /usr/lib64 -lpcap
Please edit line 1451 to : LIBPCAP_LIBS = -L/usr/lib64 -lpcap
... And make will run with no errors.
(There is the same text in the top directory Makefile line 708,
but it does not seem to disturb anything.)
The correct way with the issue would of course be to trace the bug
in Makefile.in etc., but not that easy when the files that create
the Makefile have "a thousand" upper case L.