Don't forget to look in ${LOCALBASE}/include for headers.

--- global.mak.orig	Sun Oct 10 17:11:20 2010
+++ global.mak	Sun Oct 10 17:11:31 2010
@@ -92,7 +92,7 @@ PURPLE_CFLAGS = $(CFLAGS) -DPURPLE_PLUGINS -DENABLE_NL
 PURPLE_CFLAGS += $(shell pkg-config --cflags purple)
 PURPLE_CFLAGS += $(shell pkg-config --cflags pidgin)
 #PURPLE_CFLAGS += -Wall -pthread -I. -g -O2 -pipe -fPIC -DPIC 
-PURPLE_CFLAGS += -Wall -pthread -I. -g -pipe -fPIC -DPIC
+PURPLE_CFLAGS += -Wall -pthread -I. -g -pipe -fPIC -DPIC -I${LOCALBASE}/include
 PLUGIN_SUFFIX := .so
 EXE_SUFFIX := 
 
