More specific library linking (#24)

Currently, the main binary and all output modules are linked to the same
set of libraries. This changes the linking so that only the main binary
is linked to pcap, and only addrwatch_mysql is linked to mysqlclient.

This allows the main binary and output modules to be packaged separately
with fewer dependencies for each individual package.

configure.ac

@@ -12,7 +12,7 @@ optional_modules=""
 AC_SUBST([optional_modules])
 
 # Checks for libraries.
-AC_CHECK_LIB([pcap], [pcap_open_live])
+AC_CHECK_LIB([pcap], [pcap_open_live], :)
 AC_CHECK_LIB([rt], [shm_open])
 
 PKG_CHECK_MODULES(LIBEVENT, [libevent >= 1.4], , [
@@ -46,7 +46,7 @@ AC_ARG_ENABLE([sqlite3],
 )
 AC_ARG_ENABLE([mysql],
     AS_HELP_STRING([--enable-mysql], [Enable MySQL database output]),
-    AC_CHECK_LIB([mysqlclient], [mysql_real_connect], , [
+    AC_CHECK_LIB([mysqlclient], [mysql_real_connect], :, [
     	AC_MSG_ERROR([Unable to find libmysqlclient.])
     ])
     optional_modules="${optional_modules} addrwatch_mysql"

src/Makefile.am

@@ -9,5 +9,6 @@ addrwatch_stdout_SOURCES = addrwatch_stdout.c shm_client.c shm_client.h
 addrwatch_syslog_SOURCES = addrwatch_syslog.c shm_client.c shm_client.h
 addrwatch_mysql_SOURCES = addrwatch_mysql.c shm_client.c shm_client.h util.c util.h
 
-addrwatch_LDADD = @LIBEVENT_LIBS@
+addrwatch_LDADD = @LIBEVENT_LIBS@ -lpcap
+addrwatch_mysql_LDADD = -lmysqlclient