--- OS/Makefile-Linux	2008-08-11 17:30:02.000000000 +0200
+++ OS/Makefile-Linux.oden	2010-06-06 13:34:52.567407452 +0200
@@ -10,7 +10,7 @@
 CHGRP_COMMAND=look_for_it
 CHMOD_COMMAND=look_for_it
 
-CFLAGS=-O -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE
+CFLAGS ?= -O -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE
 
 DBMLIB = -ldb
 USE_DB = yes