diff --git a/src/common.hpp b/src/common.hpp
index 2e2a89cd3c..c2c78bed77 100644
--- a/src/common.hpp
+++ b/src/common.hpp
@@ -33,6 +33,12 @@
 #endif
 #include <stdint.h>
 
+// SIZE_MAX appears to be a compiler thing not an OS header thing.
+// make sure it is defined.
+#ifndef SIZE_MAX
+    #define SIZE_MAX ((size_t)(-1))
+#endif
+
 #include <exception>
 #include <string>
 #include <vector>