diff --git a/Makefile b/Makefile
index 11defae43a82aab289474e1dab8d57ebbfe6111a..2c658d88938ca227ce67c967e53c1d1f19598eb5 100644
--- a/Makefile
+++ b/Makefile
@@ -29,7 +29,7 @@ PROGS := coalg coalgcompare
 LIBS := unix str
 SOURCESMLI := $(wildcard *.mli)
 SOURCESML := $(wildcard *.ml)
-INCS ?= -I/usr/include -I/usr/lib/ocaml
+INCS ?= -I/usr/include -I/usr/lib/ocaml -I.
 CXXFLAGS += -Wall -Werror $(INCS)
 LDXX ?= g++