# define _GLIBCXX_HAVE_FLOAT128_MATH 1
#endif
-#if __GLIBC_PREREQ(2, 27)
+#ifdef __linux__
+// The following libpthread properties only apply to Linux, not GNU/Hurd.
+
+# if __GLIBC_PREREQ(2, 27)
// Since glibc 2.27 pthread_self() is usable without linking to libpthread.
-# define _GLIBCXX_NATIVE_THREAD_ID pthread_self()
-#else
+# define _GLIBCXX_NATIVE_THREAD_ID pthread_self()
+# else
// Before then it was in libc.so.6 but not libc.a, and always returns 0,
// which breaks the invariant this_thread::get_id() != thread::id{}.
// So only use it if we know the libpthread version is available.
// Otherwise use (__gthread_t)1 as the ID of the main (and only) thread.
-# define _GLIBCXX_NATIVE_THREAD_ID \
- (__gthread_active_p() ? __gthread_self() : (__gthread_t)1)
-#endif
+# define _GLIBCXX_NATIVE_THREAD_ID \
+ (__gthread_active_p() ? __gthread_self() : (__gthread_t)1)
+# endif
-#if __GLIBC_PREREQ(2, 34)
+# if __GLIBC_PREREQ(2, 34)
// Since glibc 2.34 all pthreads functions are usable without linking to
// libpthread.
-# define _GLIBCXX_GTHREAD_USE_WEAK 0
-#endif
+# define _GLIBCXX_GTHREAD_USE_WEAK 0
+# endif
+#endif // __linux__
#endif