--- a/plugins/Makefile.in
+++ b/plugins/Makefile.in
@@ -658,7 +658,7 @@ uninstall-am: uninstall-binPROGRAMS
 all: ripperX_plugin_tester $(PLUGINS)
 
 .c.o:
-	$(CC) $(CFLAGS) $(LDFLAGS) -c $< -o $@
+	$(CC) $(CFLAGS) $(CPPFLAGS) -c $< -o $@
 
 # Tell versions [3.59,3.63) of GNU make to not export all variables.
 # Otherwise a system limit (for SysV at least) may be exceeded.