diff --git a/library/Makefile b/library/Makefile
index 85cea6b..a780267 100644
--- a/library/Makefile
+++ b/library/Makefile
@@ -165,6 +165,7 @@
 	   x509_csr.o \
 	   x509write_crt.o \
 	   x509write_csr.o \
+	   pkcs7.o \
 	   # This line is intentionally left blank
 
 OBJS_TLS= \