diff --git a/make/defs.mk b/make/defs.mk
index 292b4a2e..94ae434a 100644
--- a/make/defs.mk
+++ b/make/defs.mk
@@ -926,19 +926,19 @@ endif
 
 #include $(MODDIR)/make/lib-deps.mk
 
-BTOOLS_DIR             = $(call proj_dir, btools)
-#DSPCD_DIR              = $(call proj_dir, dspcd)
-#DSPCD_EC_DIR           = $(call proj_dir, dspcd-ec)
-FEEDFSD_DIR            = $(call proj_dir, feedfsd)
-FEEDFS_DIR             = $(call proj_dir, feedfs)
-FEEDFS_GUI_DIR         = $(call proj_dir, feedfs-gui)
-FEEDFS_OBJECTS_DIR     = $(call proj_dir, feedfs-objects)
-FEEDFS_UTILS_DIR       = $(call proj_dir, feedfs-utils)
-FEEDFS_WT_DIR          = $(call proj_dir, feedfs-wt)
-JUX_SHARED_DIR         = $(call proj_dir, jux-shared)
-SITE_DIR               = $(call proj_dir, site)
-VALDI_DIR              = $(call proj_dir, valdi)
-XCHANGE_DIR            = $(call proj_dir, xchange)
+BTOOLS_DIR             ?= $(call proj_dir, btools)
+#DSPCD_DIR              ?= $(call proj_dir, dspcd)
+#DSPCD_EC_DIR           ?= $(call proj_dir, dspcd-ec)
+FEEDFSD_DIR            ?= $(call proj_dir, feedfsd)
+FEEDFS_DIR             ?= $(call proj_dir, feedfs)
+FEEDFS_GUI_DIR         ?= $(call proj_dir, feedfs-gui)
+FEEDFS_OBJECTS_DIR     ?= $(call proj_dir, feedfs-objects)
+FEEDFS_UTILS_DIR       ?= $(call proj_dir, feedfs-utils)
+FEEDFS_WT_DIR          ?= $(call proj_dir, feedfs-wt)
+JUX_SHARED_DIR         ?= $(call proj_dir, jux-shared)
+SITE_DIR               ?= $(call proj_dir, site)
+VALDI_DIR              ?= $(call proj_dir, valdi)
+XCHANGE_DIR            ?= $(call proj_dir, xchange)
 
 #PREREQ_INSTALL            ?= $(PREREQ_BUILD)
 #PREREQ_RUN                ?= $(PREREQ_INSTALL)