pmcd/agent.c - remove compilation warnings
pmcd/agent.c - remove compilation warnings

For Windows builds, added some conditional code to completely
hide unused variable.

edwardt/pcp,andyvand/cygpcpfans,adfernandes/pcp,wuliming/pcp,ryandoyle/pcp_original,ryandoyle/pcp_original,aeg-aeg/pcpfans,ryandoyle/pcp_original,andyvand/cygpcpfans,tjanez/pcp,mbaldessari/pcp,ryandoyle/pcp_original,edwardt/pcp,adfernandes/pcp,ryandoyle/pcp_original,ryandoyle/pcp_original,andyvand/cygpcpfans,adfernandes/pcp,prasincs/pcp,edwardt/pcp,adfernandes/pcp,edwardt/pcp,tjanez/pcp,wuliming/pcp,wuliming/pcp,andyvand/cygpcpfans,ryandoyle/pcp_original,edwardt/pcp,wuliming/pcp,ryandoyle/pcp_original,prasincs/pcp,mbaldessari/pcp,prasincs/pcp,prasincs/pcp,prasincs/pcp,andyvand/cygpcpfans,adfernandes/pcp,tjanez/pcp,mbaldessari/pcp,edwardt/pcp,aeg-aeg/pcpfans,tjanez/pcp,wuliming/pcp,tjanez/pcp,aeg-aeg/pcpfans,tjanez/pcp,adfernandes/pcp,prasincs/pcp,wuliming/pcp,andyvand/cygpcpfans,tjanez/pcp,wuliming/pcp,wuliming/pcp,aeg-aeg/pcpfans,mbaldessari/pcp,aeg-aeg/pcpfans,mbaldessari/pcp,prasincs/pcp,andyvand/cygpcpfans,tjanez/pcp,edwardt/pcp,adfernandes/pcp,aeg-aeg/pcpfans,adfernandes/pcp,prasincs/pcp,edwardt/pcp,aeg-aeg/pcpfans,aeg-aeg/pcpfans,mbaldessari/pcp,andyvand/cygpcpfans