diff --git a/Makefile.am b/Makefile.am
index bbbe6c13..8305262c 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -17,7 +17,7 @@ MKDIR=mkdir -p
 
 # -Wno-endif-labels : Needed to prevent warnings in ieee80.c.
 AM_CFLAGS = \
-	-Isrc/include -Isrc/include/compat -I src/ucd-tools/src/include \
+	-Isrc/include -Isrc/include/compat -I$(srcdir)/src/ucd-tools/src/include \
 	-D_BSD_SOURCE -D_DEFAULT_SOURCE -D_POSIX_C_SOURCE=200112L \
 	-Wno-endif-labels