diff --git a/lib/sha2.c b/lib/sha2.c
index eda9f1a3..81cee1c0 100644
--- a/lib/sha2.c
+++ b/lib/sha2.c
@@ -36,6 +36,10 @@
 #include <assert.h>	/* assert() */
 #include "sha2.h"
 
+#if HAVE_SYS_BYTEORDER_H
+  #include <sys/byteorder.h>
+#endif
+
 /*
  * ASSERT NOTE:
  * Some sanity checking code is included using assert().  On my FreeBSD
@@ -86,8 +90,14 @@
  * made).
  */
 
-#ifdef WIN32
-  #define BYTE_ORDER BIG_ENDIAN
+#ifndef BYTE_ORDER
+  #ifdef WIN32
+    #define BYTE_ORDER BIG_ENDIAN
+  #elif defined(_BIG_ENDIAN)
+    #define BYTE_ORDER BIG_ENDIAN
+  #elif defined(_LITTLE_ENDIAN)
+    #define BYTE_ORDER LITTLE_ENDIAN
+  #endif
 #endif
 
 #if !defined(BYTE_ORDER) || (BYTE_ORDER != LITTLE_ENDIAN && BYTE_ORDER != BIG_ENDIAN)
diff --git a/lib/sha2.h b/lib/sha2.h
index 190b697d..8b6e6f40 100644
--- a/lib/sha2.h
+++ b/lib/sha2.h
@@ -48,6 +48,10 @@ extern "C" {
  */
 #include <sys/types.h>
 
+#if HAVE_INTTYPES_H
+  #define SHA2_USE_INTTYPES_H
+#endif
+
 #ifdef SHA2_USE_INTTYPES_H
   #include <inttypes.h>
 #endif /* SHA2_USE_INTTYPES_H */