diff --git a/include/internal/e_os.h b/include/internal/e_os.h
index db05b7f8150f8..09b3e2a8fc3a9 100644
--- a/include/internal/e_os.h
+++ b/include/internal/e_os.h
@@ -16,6 +16,7 @@
 # include <openssl/e_os2.h>
 # include <openssl/crypto.h>
 # include "internal/nelem.h"
+# include "internal/numbers.h"   /* Ensure the definition of SIZE_MAX */
 
 /*
  * <openssl/e_os2.h> contains what we can justify to make visible to the