Index: src/driver/cfa.cc
===================================================================
--- src/driver/cfa.cc	(revision 4b1afb612226e0433d5fc67b4d46e47789cfa3df)
+++ src/driver/cfa.cc	(revision 1f44196dc72fd060b6183fe2bdc10f7b30f955d6)
@@ -244,4 +244,6 @@
 		nargs += 1;
 	} // if
+	args[nargs] = "-I" CFA_INCDIR "/concurrency";
+	nargs += 1;
 	args[nargs] = "-I" CFA_INCDIR "/containers";
 	nargs += 1;