patch 8.2.4144: cannot load libsodium dynamically

Problem:    Cannot load libsodium dynamically.
Solution:   Support dynamic loading on MS-Windows. (Ken Takata, closes #9554)
diff --git a/src/memline.c b/src/memline.c
index a42c5f1..56f6958 100644
--- a/src/memline.c
+++ b/src/memline.c
@@ -436,7 +436,8 @@
 	}
 #ifdef FEAT_SODIUM
 	else if (method_nr == CRYPT_M_SOD)
-	    randombytes_buf(buf->b_ml.ml_mfp->mf_seed, MF_SEED_LEN);
+	    crypt_sodium_randombytes_buf(buf->b_ml.ml_mfp->mf_seed,
+							    MF_SEED_LEN);
  #endif
     }
 }