diff --git a/lib/isc/include/isc/endian.h b/lib/isc/include/isc/endian.h
index 30a8f1e076..f0ceab6417 100644
--- a/lib/isc/include/isc/endian.h
+++ b/lib/isc/include/isc/endian.h
@@ -11,32 +11,8 @@
 
 #pragma once
 
-#if defined __APPLE__
-
-#include <libkern/OSByteOrder.h>
-
-# define htobe16(x) OSSwapHostToBigInt16(x)
-# define htole16(x) OSSwapHostToLittleInt16(x)
-# define be16toh(x) OSSwapBigToHostInt16(x)
-# define le16toh(x) OSSwapLittleToHostInt16(x)
-
-# define htobe32(x) OSSwapHostToBigInt32(x)
-# define htole32(x) OSSwapHostToLittleInt32(x)
-# define be32toh(x) OSSwapBigToHostInt32(x)
-# define le32toh(x) OSSwapLittleToHostInt32(x)
-
-# define htobe64(x) OSSwapHostToBigInt64(x)
-# define htole64(x) OSSwapHostToLittleInt64(x)
-# define be64toh(x) OSSwapBigToHostInt64(x)
-# define le64toh(x) OSSwapLittleToHostInt64(x)
-
-# define __BYTE_ORDER    BYTE_ORDER
-# define __BIG_ENDIAN    BIG_ENDIAN
-# define __LITTLE_ENDIAN LITTLE_ENDIAN
-# define __PDP_ENDIAN    PDP_ENDIAN
-
-#elif defined(__DragonFly__) || defined(__FreeBSD__) || \
-      defined(__NetBSD__) || defined (__OpenBSD__) || defined(__bsdi__)
+#if defined(__DragonFly__) || defined(__FreeBSD__) || \
+    defined(__NetBSD__) || defined (__OpenBSD__) || defined(__bsdi__)
 
 # include <sys/endian.h>
 
@@ -79,6 +55,29 @@
 # define __LITTLE_ENDIAN LITTLE_ENDIAN
 # define __PDP_ENDIAN    PDP_ENDIAN
 
+#elif defined __APPLE__
+
+/*
+ * macOS has its own byte-swapping routines, so use these.
+ */
+
+# include <libkern/OSByteOrder.h>
+
+# define htobe16(x) OSSwapHostToBigInt16(x)
+# define htole16(x) OSSwapHostToLittleInt16(x)
+# define be16toh(x) OSSwapBigToHostInt16(x)
+# define le16toh(x) OSSwapLittleToHostInt16(x)
+
+# define htobe32(x) OSSwapHostToBigInt32(x)
+# define htole32(x) OSSwapHostToLittleInt32(x)
+# define be32toh(x) OSSwapBigToHostInt32(x)
+# define le32toh(x) OSSwapLittleToHostInt32(x)
+
+# define htobe64(x) OSSwapHostToBigInt64(x)
+# define htole64(x) OSSwapHostToLittleInt64(x)
+# define be64toh(x) OSSwapBigToHostInt64(x)
+# define le64toh(x) OSSwapLittleToHostInt64(x)
+
 #elif defined(sun) || defined(__sun) || defined(__SVR4)
 
 /*