Fix flex linking order

We need to specify -lfl after docsis.o, because libfl provides a main()
function.  Why it does this is beyond me.

This fixes #45.

src/Makefile.am

@@ -5,7 +5,7 @@ docsis_SOURCES = docsis.c ethermac.c md5.c docsis_encode.c docsis_decode.c docsi
 AM_CPPFLAGS = $(all_includes) $(NETSNMP_CFLAGS)
 
 # the library search path.
-docsis_LDFLAGS = $(all_libraries) $(NETSNMP_LIBS) $(LEXLIB) $(LIBM)
+docsis_LDADD = $(all_libraries) $(NETSNMP_LIBS) $(LEXLIB) $(LIBM)
 noinst_HEADERS = ethermac.h md5.h docsis.h docsis_common.h docsis_decode.h docsis_encode.h docsis_symtable.h docsis_snmp.h docsis_globals.h
 EXTRA_DIST=docsis_yy.h
 CLEANFILES=docsis_yy.c docsis_yy.h docsis_yy.output docsis_lex.c