Explicit conversions and minor changes to prevent MSVC compiler warnings
diff --git a/library/x509write_csr.c b/library/x509write_csr.c
index 1eb2afb..febed67 100644
--- a/library/x509write_csr.c
+++ b/library/x509write_csr.c
@@ -209,7 +209,7 @@
     ASN1_CHK_ADD( len, asn1_write_len( &c2, buf, len ) );
     ASN1_CHK_ADD( len, asn1_write_tag( &c2, buf, ASN1_CONSTRUCTED | ASN1_SEQUENCE ) );
 
-    return( len );
+    return( (int) len );
 }
 
 #define PEM_BEGIN_CSR           "-----BEGIN CERTIFICATE REQUEST-----\n"