Add thread support

include/bh/internal/thread.h

@@ -0,0 +1,45 @@
+#ifndef BHLIB_INTERNAL_THREAD_H
+#define BHLIB_INTERNAL_THREAD_H
+
+#include <bh/thread.h>
+#include "queue.h"
+
+#define BH_THREAD_DONE      (1 << 8)
+
+#if defined(BHLIB_USE_PTHREAD)
+#include "thread_posix.h"
+#elif defined(BHLIB_USE_WINTHREAD)
+#include "thread_win.h"
+#else
+#include "thread_null.h"
+#endif
+
+struct bh_task_s
+{
+    void (*func)(void *);
+    void *data;
+    int flags;
+};
+
+struct bh_thread_pool_s
+{
+    bh_thread_t *threads;
+    bh_queue_t tasks;
+    bh_mutex_t lock;
+    bh_cond_t new_task;
+    bh_cond_t done_task;
+    size_t size;
+    size_t active;
+    int shutdown;
+};
+
+void bh_task_init(bh_task_t *task,
+                  void (*func)(void *),
+                  void *data,
+                  int flags);
+
+void bh_task_destroy(bh_task_t *task);
+
+void bh_thread_pool_worker(void *arg);
+
+#endif /* BHLIB_INTERNAL_THREAD_H */