diff --git a/usr.bin/xlint/lint1/param.h b/usr.bin/xlint/lint1/param.h
index e7926d98879..b5624035827 100644
--- a/usr.bin/xlint/lint1/param.h
+++ b/usr.bin/xlint/lint1/param.h
@@ -80,6 +80,9 @@
 #elif __sparc__
 #define PTRDIFF_IS_LONG		0
 #define SIZEOF_IS_ULONG		0
+#elif __sparc64__
+#define PTRDIFF_IS_LONG		1
+#define SIZEOF_IS_ULONG		1
 #elif __vax__
 #define PTRDIFF_IS_LONG         0
 #define SIZEOF_IS_ULONG         0