Fix with nettle >=4

Index: lib/rc-md5.c
--- lib/rc-md5.c.orig
+++ lib/rc-md5.c
@@ -20,10 +20,10 @@
 void rc_md5_calc(unsigned char *output, unsigned char const *input,
 		 size_t inlen)
 {
-	MD5_CTX	context;
+	struct md5_ctx context;
 
-	MD5Init(&context);
-	MD5Update(&context, input, inlen);
-	MD5Final(output, &context);
+	md5_init(&context);
+	md5_update(&context, inlen, input);
+	md5_digest(&context, output);
 }
 
