diff -r e2ed40f0eb2e -r 98042b0e19f9 mercurial/util.h
--- a/mercurial/util.h	Wed Mar 25 14:13:11 2015 -0500
+++ b/mercurial/util.h	Wed Mar 25 14:16:10 2015 -0500
@@ -209,4 +209,13 @@
 	return ret;
 }
 
+/* VC9 doesn't include bool and lacks stdbool.h based on my searching */
+#ifdef _MSC_VER
+#define true 1
+#define false 0
+typedef unsigned char bool;
+#else
+#include <stdbool.h>
+#endif
+
 #endif /* _HG_UTIL_H_ */