diff --git a/src/block_if.c b/src/block_if.c
index 25d6e79..529d8be 100644
--- a/src/block_if.c
+++ b/src/block_if.c
@@ -121,6 +121,8 @@ static struct blockif_sig_elem *blockif_bse_head;
 
 #pragma clang diagnostic pop
 
+#if !defined(__MAC_10_16)
+
 static ssize_t
 preadv(int fd, const struct iovec *iov, int iovcnt, off_t offset)
 {
@@ -141,6 +143,8 @@ pwritev(int fd, const struct iovec *iov, int iovcnt, off_t offset)
 	return writev(fd, iov, iovcnt);
 }
 
+#endif
+
 static int
 blockif_enqueue(struct blockif_ctxt *bc, struct blockif_req *breq,
 		enum blockop op)
diff --git a/src/pci_e82545.c b/src/pci_e82545.c
index aac672c..269a05e 100644
--- a/src/pci_e82545.c
+++ b/src/pci_e82545.c
@@ -1412,8 +1412,11 @@ e82545_transmit(struct e82545_softc *sc, uint16_t head, uint16_t tail,
 
 	/* Allocate, fill and prepend writable header vector. */
 	if (hdrlen != 0) {
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Walloca"
 		hdr = __builtin_alloca((size_t)(hdrlen + vlen));
-		hdr += vlen;
+#pragma clang diagnostic push
+        hdr += vlen;
 		for (left = hdrlen, hdrp = hdr; left > 0;
 		    left -= now, hdrp += now) {
 			now = MIN(left, (int)(iov->iov_len));