pidgin/purple-plugin-pack

updated the pkg-config macros to use libpurple-3 and pidgin-3
#
# Makefile.mingw
#
# Description: Makefile for timelog plugin.
#
PP_TOP := ..
PP = timelog
PP_SRC := \
log-widget.c \
range-widget.c \
timelog.c
include $(PP_TOP)/win_pp.mak