perfschema: native type for my_thread_os_id_t

Though these will all get case to unsigned long
long where it is populated into the perfschema's BIGINT
type.

Use uintptr_t for NetBSD per Nia Alarie's original #1836.

storage/perfschema/my_thread.h

@@ -17,7 +17,17 @@
 typedef pthread_key_t thread_local_key_t;
 typedef pthread_t my_thread_handle;
 typedef pthread_attr_t my_thread_attr_t;
+#if defined(HAVE_PTHREAD_THREADID_NP) || defined(HAVE_GETTID) || defined(HAVE_SYS_GETTID) || defined(HAVE_GETTHRID)
+typedef pid_t my_thread_os_id_t;
+#elif defined(_WIN32)
+typedef uint32 my_thread_os_id_t;
+#elif defined(HAVE_PTHREAD_GETTHREADID_NP)
+typedef int my_thread_os_id_t;
+#elif defined(HAVE_INTEGER_PTHREAD_SELF)
+typedef uintptr_t my_thread_os_id_t;
+#else
 typedef unsigned long long my_thread_os_id_t;
+#endif
 
 #define LOCK_plugin_delete LOCK_plugin
 
@@ -74,8 +84,8 @@ static inline my_thread_os_id_t my_thread_os_id()
   return getthrid();
 #else
 #ifdef HAVE_INTEGER_PTHREAD_SELF
-  /* Unknown platform, fallback. */
-  return (unsigned long long)pthread_self();
+  /* NetBSD, and perhaps something else, fallback. */
+  return (my_thread_os_id_t) pthread_self();
 #else
   /* Feature not available. */
   return 0;