diff --git a/doc/examples/makefile.am b/doc/examples/makefile.am
index 419649c..b54dcbc 100644
--- a/doc/examples/makefile.am
+++ b/doc/examples/makefile.am
@@ -8,7 +8,7 @@ noinst_PROGRAMS = pcsc-demo cryptoki-demo openssl-tcp-demo openssl-ssl-demo
 AM_CPPFLAGS = -I${top_srcdir}/src
 if !MINGW32
 if MAC
-AM_CPPFLAGS += /opt/local/include
+AM_CPPFLAGS += -I/opt/local/include
 else
 AM_CPPFLAGS += -I/usr/include/PCSC
 endif