diff --git a/headers/posix/stdint.h b/headers/posix/stdint.h
index eb07104a5a..f94f945498 100644
--- a/headers/posix/stdint.h
+++ b/headers/posix/stdint.h
@@ -136,16 +136,22 @@ typedef uint64_t uintmax_t;
 #define INT8_C(value) 	value
 #define INT16_C(value) 	value
 #define INT32_C(value) 	value
-#define INT64_C(value) 	value ## LL
 
 #define UINT8_C(value) 	value ## U
 #define UINT16_C(value) value ## U
 #define UINT32_C(value) value ## U
-#define UINT64_C(value) value ## ULL
 
-/* Macros for greatest-width integer constant expressions */
+#if defined(__SIZEOF_LONG__) && __SIZEOF_LONG__ > 4
+#define INT64_C(value)		value ## L
+#define UINT64_C(value) 	value ## UL
+#define INTMAX_C(value) 	value ## L
+#define UINTMAX_C(value)	value ## UL
+#else
+#define INT64_C(value) 		value ## LL
+#define UINT64_C(value) 	value ## ULL
 #define INTMAX_C(value) 	value ## LL
-#define UINTMAX_C(value) 	value ## ULL
+#define UINTMAX_C(value)	value ## ULL
+#endif
 
 #endif /* !defined(__cplusplus) || defined(__STDC_CONSTANT_MACROS) */