Avoid reinterpret_cast to same type

...as GCC 4.6 reports "error: invalid cast from type 'pthread_t {aka long
unsigned int}' to type 'long unsigned int'" despite [expr.reinterpret.cast]/2:
"An expression of integral, enumeration, pointer, or pointer-to-member type can
be explicitly converted to its own type; such a cast yields the value of its
operand."

Change-Id: I26f1a3e6df2f0e55c665ad4f49185e0ebf432e95

sal/osl/unx/system.hxx

@@ -309,9 +309,12 @@ int macxp_resolveAlias(char *path, int buflen);
 #   define  INIT_GROUPS(name, gid)  ((setgid((gid)) == 0) && (initgroups((name), (gid)) == 0))
 #endif
 
-#ifndef PTHREAD_VALUE
-#   define PTHREAD_VALUE(t)             (t)
+#if defined MACOSX
+#define PTHREAD_VALUE(t) reinterpret_cast<unsigned long>(t)
+#else
+#define PTHREAD_VALUE(t) (t)
 #endif
+
 #ifndef PTHREAD_NONE
 #   define PTHREAD_NONE                 _pthread_none_
 #   ifndef PTHREAD_NONE_INIT

sal/osl/unx/thread.cxx

@@ -551,7 +551,7 @@ void SAL_CALL osl_setThreadName(char const * name) {
 /* osl_getThreadIdentifier @@@ see TODO @@@ */
 /*****************************************************************************/
 
-#define HASHID(x) (reinterpret_cast<unsigned long>(PTHREAD_VALUE(x)) % HashSize)
+#define HASHID(x) ((unsigned long)PTHREAD_VALUE(x) % HashSize)
 
 typedef struct _HashEntry
 {