c11: #include <threads.h> when the os/platform provide it

Closes #6964

CC: mesa-stable

Signed-off-by: Yonggang Luo <luoyonggang@gmail.com>
Reviewed-by: Jesse Natalie <jenatali@microsoft.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18043>

src/c11/impl/meson.build

@@ -22,7 +22,9 @@ files_mesa_util_c11 = files(
   'time.c',
 )
 
-if host_machine.system() == 'windows'
+if with_c11_threads
+  # no need implement c11 threads
+elif host_machine.system() == 'windows'
   files_mesa_util_c11 += 'threads_win32.c'
   files_mesa_util_c11 += 'threads_win32_tls_callback.cpp'
 else

src/c11/threads.h

@@ -47,6 +47,20 @@
 #  error Not supported on this platform.
 #endif
 
+#if defined(HAVE_THRD_CREATE)
+#include <threads.h>
+
+#if defined(ANDROID)
+/* Currently, only Android are verified that it's thrd_t are typedef of pthread_t
+ * So we can define _MTX_INITIALIZER_NP to PTHREAD_MUTEX_INITIALIZER
+ * FIXME: temporary non-standard hack to ease transition
+ */
+#  define _MTX_INITIALIZER_NP PTHREAD_MUTEX_INITIALIZER
+#else
+#error Can not define _MTX_INITIALIZER_NP properly for this platform
+#endif
+#else
+
 /*---------------------------- macros ---------------------------*/
 
 #ifndef _Thread_local
@@ -185,4 +199,6 @@ int tss_set(tss_t, void *);
 }
 #endif
 
+#endif /* HAVE_THRD_CREATE */
+
 #endif /* C11_THREADS_H_INCLUDED_ */