Unify csr and crt san writing functions

Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
diff --git a/library/Makefile b/library/Makefile
index fafcdda..8bddd7d 100644
--- a/library/Makefile
+++ b/library/Makefile
@@ -166,6 +166,7 @@
 	   x509_crl.o \
 	   x509_crt.o \
 	   x509_csr.o \
+   	   x509write.o \
 	   x509write_crt.o \
 	   x509write_csr.o \
 	   pkcs7.o \