[Click] external library

[Jack Chan]

I am trying to build a new package in which I use mysql through mysql++ at
userlevel. I can compile and install, but when I run a configuration, I got
undefined symbol error:

While loading package 'sql':
  package /home/jack/lib/sql.uo: undefined symbol:
_ZN7mysqlpp10Connection7connectEPKcS2_S2_S2_jcjS2_j

I have modified Makefile.in as:
INCLUDES = -I. -I$(top_builddir) -I$(srcdir) $(CLICKINCLUDES)
-I/home/jack/include/mysql/ -I/home/jack/include/mysql++/
LDFLAGS = $(CLICKLDFLAGS)  -L/home/jack/lib -L/home/jack/lib/mysql

I found a couple of similar requests in mailinglist archive, but couldn't
figure out the solution that worked. Also looked the Makefile.in of the RON
package, but not fruitful. Are there general guidelines on using external
libraries in packages?

Also, I got undefined symbol errors when using my non-element classes, how
do I "export" them?

Thanks,
Jack