diff --git a/core/plug-in/sipctrl/hash.cpp b/core/plug-in/sipctrl/hash.cpp
index 7b0e9839..b13d798d 100644
--- a/core/plug-in/sipctrl/hash.cpp
+++ b/core/plug-in/sipctrl/hash.cpp
@@ -45,13 +45,14 @@ on 1 byte), but shoehorning those bytes into integers efficiently is messy.
 /*
  * My best guess at if you are big-endian or little-endian.  This may
  * need adjustment.
+ * Update 20080211, Richard Newman: I think this fits in better with the
+ * code elsewhere in SEMS, which started off using just __BYTE_ORDER. I
+ * extended it to work on Solaris, too.
  */
-#if (defined(BYTE_ORDER) && defined(LITTLE_ENDIAN) && \
-     BYTE_ORDER == LITTLE_ENDIAN)
+#if (defined(__BYTE_ORDER) && (__BYTE_ORDER == __LITTLE_ENDIAN)) || defined(_LITTLE_ENDIAN) || defined(__LITTLE_ENDIAN)
 # define HASH_LITTLE_ENDIAN 1
 # define HASH_BIG_ENDIAN 0
-#elif (defined(BYTE_ORDER) && defined(BIG_ENDIAN) && \
-       BYTE_ORDER == BIG_ENDIAN)
+#elif (defined(__BYTE_ORDER) && (__BYTE_ORDER == __BIG_ENDIAN)) || defined(_BIG_ENDIAN) || defined(__BIG_ENDIAN)
 # define HASH_LITTLE_ENDIAN 0
 # define HASH_BIG_ENDIAN 1
 #else