diff --git a/expat/Changes b/expat/Changes
index 7030cbd0..d1693b73 100644
--- a/expat/Changes
+++ b/expat/Changes
@@ -14,10 +14,12 @@ Release 2.2.? ????????????????
              #23  Test suite: Fix memory leaks
                   Rely on macro HAVE_ARC4RANDOM_BUF (rather than __CloudABI__)
                     for CloudABI
+            #100  Fix use of SIPHASH_MAIN in siphash.h
 
         Special thanks to:
             Pascal Cuoq
             Rhodri James
+            Vadim Zeitlin
             Viktor Szakats
                  and
             Core Infrastructure Initiative
diff --git a/expat/lib/siphash.h b/expat/lib/siphash.h
index 30a6f11d..581872df 100644
--- a/expat/lib/siphash.h
+++ b/expat/lib/siphash.h
@@ -11,6 +11,9 @@
  * --------------------------------------------------------------------------
  * HISTORY:
  *
+ * 2017-07-25  (Vadim Zeitlin)
+ *   - Fix use of SIPHASH_MAIN macro
+ *
  * 2017-07-05  (Sebastian Pipping)
  *   - Use _SIP_ULL macro to not require a C++11 compiler if compiled as C++
  *   - Add const qualifiers at two places
@@ -350,7 +353,7 @@ static int sip24_valid(void) {
 } /* sip24_valid() */
 
 
-#if SIPHASH_MAIN
+#ifdef SIPHASH_MAIN
 
 #include <stdio.h>