diff --git a/examples/sample.source.PKIX1/Makefile b/examples/sample.source.PKIX1/Makefile
index 26ca748..8f902b2 100644
--- a/examples/sample.source.PKIX1/Makefile
+++ b/examples/sample.source.PKIX1/Makefile
@@ -345,7 +345,7 @@
 # This file may be used as an input for make(3)
 # Remove the lines below to convert it into a pure .am file
 TARGET = x509dump
-CFLAGS += -I. -DHAVE_CONFIG_H -DPDU=Certificate
+CFLAGS += -I.  -DHAVE_CONFIG_H -DPDU=Certificate
 OBJS=${ASN_MODULE_SOURCES:.c=.o} ${ASN_CONVERTER_SOURCES:.c=.o}
 
 all: Certificate.c $(TARGET)