types: add C99-style constructors to <asm-generic/int-*.h>

Add C99-style constructor macros for fixed types to
<asm-generic/int-*.h>.  Since Linux uses names like "u64" instead of
"uint64_t", the constructor macros are called U64_C() instead of
UINT64_C() and so forth.

These macros allow specific sizes to be specified as
U64_C(0x123456789abcdef), without gcc issuing warnings as it will if
one writes (u64)0x123456789abcdef.

When used from assembly, these macros pass their argument unchanged.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
diff --git a/include/asm-generic/int-l64.h b/include/asm-generic/int-l64.h
index 629b5a4..2af9b75 100644
--- a/include/asm-generic/int-l64.h
+++ b/include/asm-generic/int-l64.h
@@ -44,6 +44,26 @@
 typedef signed long s64;
 typedef unsigned long u64;
 
+#define S8_C(x)  x
+#define U8_C(x)  x ## U
+#define S16_C(x) x
+#define U16_C(x) x ## U
+#define S32_C(x) x
+#define U32_C(x) x ## U
+#define S64_C(x) x ## L
+#define U64_C(x) x ## UL
+
+#else /* __ASSEMBLY__ */
+
+#define S8_C(x)  x
+#define U8_C(x)  x
+#define S16_C(x) x
+#define U16_C(x) x
+#define S32_C(x) x
+#define U32_C(x) x
+#define S64_C(x) x
+#define U64_C(x) x
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* __KERNEL__ */