diff --git a/src/runtime/c/pgf/pgf.h b/src/runtime/c/pgf/pgf.h
index b8f866cd6..7c991f440 100644
--- a/src/runtime/c/pgf/pgf.h
+++ b/src/runtime/c/pgf/pgf.h
@@ -128,7 +128,7 @@ typedef struct {
 #define LINT_BASE 1000000000
 #define LINT_BASE_LOG 9
 #elif __WORDSIZE == 64
-#define LINT_BASE 10000000000000000000
+#define LINT_BASE 10000000000000000000UL
 #define LINT_BASE_LOG 19
 #else
 #error "Platforms with the current __WORDSIZE are not supported yet"