diff --git a/configure/RULES.Db b/configure/RULES.Db
index aea72b6a8..27b3092d7 100644
--- a/configure/RULES.Db
+++ b/configure/RULES.Db
@@ -24,7 +24,7 @@ vpath %.acs $(USR_VPATH) $(GENERIC_SRC_DIRS) $(COMMON_DIR)
 # dbExpand
 INSTALL_DBDFLAGS += -I $(INSTALL_DBD)
 INSTALL_DBFLAGS += -I $(INSTALL_DB)
-DBDFLAGS = $(USR_DBDFLAGS) -I. -I.. -I$(COMMON_DIR) $(INSTALL_DBDFLAGS) $(RELEASE_DBDFLAGS)
+DBDFLAGS = $(USR_DBDFLAGS) $(addprefix -I,. .. $(COMMON_DIR) $(SRC_DIRS)) $(INSTALL_DBDFLAGS) $(RELEASE_DBDFLAGS)
 DBFLAGS = $($*_DBFLAGS) $(USR_DBFLAGS) -I. -I.. -I$(COMMON_DIR) $(INSTALL_DBFLAGS) $(RELEASE_DBFLAGS)
 
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