LibC: Implement pthread_barrier

This is not fully working but should be fine for most cases

userspace/libraries/LibC/include/bits/pthread_types.h

@@ -28,8 +28,8 @@ typedef pthread_t pthread_spinlock_t;
 typedef struct { int type; int shared; } pthread_mutexattr_t;
 typedef struct { pthread_mutexattr_t attr; pthread_t locker; unsigned lock_depth; } pthread_mutex_t;
 
-typedef int pthread_barrierattr_t;
-typedef int pthread_barrier_t;
+typedef struct { int shared; } pthread_barrierattr_t;
+typedef struct { pthread_barrierattr_t attr; unsigned target; unsigned waiting; } pthread_barrier_t;
 
 typedef struct { int clock; int shared; } pthread_condattr_t;
 struct _pthread_cond_block { struct _pthread_cond_block* next; int signaled; };

userspace/libraries/LibC/include/pthread.h

@@ -24,7 +24,6 @@ struct uthread
 	uintptr_t dtv[];
 };
 
-#define PTHREAD_BARRIER_SERIAL_THREAD	1
 #define PTHREAD_CANCEL_ASYNCHRONOUS		2
 #define PTHREAD_CANCEL_ENABLE			3
 #define PTHREAD_CANCEL_DEFERRED			4
@@ -40,6 +39,8 @@ struct uthread
 #define PTHREAD_SCOPE_PROCESS			23
 #define PTHREAD_SCOPE_SYSTEM			24
 
+#define PTHREAD_BARRIER_SERIAL_THREAD	1
+
 #define PTHREAD_ONCE_INIT				0
 
 #define PTHREAD_PROCESS_SHARED			0