diff --git a/make/projects-dir.mk b/make/projects-dir.mk
index 08f5938f..7ab05c53 100644
--- a/make/projects-dir.mk
+++ b/make/projects-dir.mk
@@ -60,8 +60,14 @@ endif
 BUILD_PROJECTS = $(filter-out $(EXCLUDE_FROM_BUILD),$(PROJECTS))
 
 ifndef JANWARE_USER
-  export JANWARE_USER = $(shell id -un)
+  ifneq ($(wildcard CVS/Root),)
+    JANWARE_USER = $(shell sed '/^:ext/ !d; s/:ext:\([^@]\+\)@.*/\1/' CVS/Root)
+    $(info Taking JANWARE_USER=$(JANWARE_USER) from CVS/Root)
+  else
+    JANWARE_USER = $(shell id -un)
+  endif
   $(warning Assuming JANWARE_USER=$(JANWARE_USER), explicitly set environment variable to turn off this warning!)
+  export JANWARE_USER
 endif
 
 ifeq ($(JANWARE_USER),)