Define opal_int128_t type if a 128-bit integer is available.

There currently is no standard support for 128-bit integer types. Any use
of the __int128 and int128_t types can lead to warnings from the compiler
when using -Wpedantic. Additionally, some compilers may support __int128
and other may support int128_t. This commit addresses both issues by
defining opal_int128_t if there is a supported 128-bit type. In the
case of GCC a pragma has been added to suppress warnings about __int128
not being a standard C type.

opal/include/opal/sys/amd64/atomic.h

@@ -122,10 +122,10 @@ static inline int opal_atomic_cmpset_64( volatile int64_t *addr,
 #define opal_atomic_cmpset_acq_64 opal_atomic_cmpset_64
 #define opal_atomic_cmpset_rel_64 opal_atomic_cmpset_64
 
-#if OPAL_GCC_INLINE_ASSEMBLY && OPAL_HAVE_CMPXCHG16B && HAVE___INT128
+#if OPAL_GCC_INLINE_ASSEMBLY && OPAL_HAVE_CMPXCHG16B && HAVE_OPAL_INT128_T
 
-static inline __int128 opal_atomic_cmpset_128 (volatile __int128 *addr, __int128 oldval,
-                                               __int128 newval)
+static inline opal_int128_t opal_atomic_cmpset_128 (volatile opal_int128_t *addr, opal_int128_t oldval,
+                                                    opal_int128_t newval)
 {
     unsigned char ret;
 

opal/include/opal/sys/atomic.h

@@ -49,10 +49,7 @@
 #include "opal_config.h"
 
 #include "opal/sys/architecture.h"
-
-#ifdef HAVE_SYS_TYPES_H
-#include <sys/types.h>
-#endif
+#include "opal_stdint.h"
 
 /* do some quick #define cleanup in cases where we are doing
    testing... */

opal/include/opal_stdint.h

@@ -134,6 +134,33 @@ typedef unsigned long long uint64_t;
 
 #endif
 
+/* 128-bit */
+
+#ifdef HAVE_INT128_T
+
+typedef int128_t opal_int128_t;
+typedef uint128_t opal_uint128_t;
+
+#define HAVE_OPAL_INT128_T 1
+
+#elif HAVE___INT128
+
+/* suppress warning about __int128 type */
+#pragma GCC diagnostic ignored "-Wpedantic"
+typedef __int128 opal_int128_t;
+
+/* suppress warning about __int128 type */
+#pragma GCC diagnostic ignored "-Wpedantic"
+typedef unsigned __int128 opal_uint128_t;
+
+#define HAVE_OPAL_INT128_T 1
+
+#else
+
+#define HAVE_OPAL_INT128_T 0
+
+#endif
+
 /* Pointers */
 
 #if SIZEOF_VOID_P == SIZEOF_INT