kernel: Add posix API for semaphore

Add semaphore posix APIs.

Signed-off-by: Punit Vara <punit.vara@intel.com>

include/posix/pthread.h

@@ -157,7 +157,6 @@ static inline int pthread_condattr_destroy(pthread_condattr_t *att)
 		.sem = &name##_psem,		\
 	}
 
-
 /**
  * @brief POSIX threading compatibility API
  *

include/posix/semaphore.h

@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2018 Intel Corporation
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#ifndef _POSIX_SEMAPHORE_H
+#define _POSIX_SEMAPHORE_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "sys/types.h"
+#include <time.h>
+
+int sem_destroy(sem_t *semaphore);
+int sem_getvalue(sem_t *semaphore, int *value);
+int sem_init(sem_t *semaphore, int pshared, unsigned int value);
+int sem_post(sem_t *semaphore);
+int sem_timedwait(sem_t *semaphore, struct timespec *abstime);
+int sem_trywait(sem_t *semaphore);
+int sem_wait(sem_t *semaphore);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* POSIX_SEMAPHORE_H */

include/posix/sys/types.h

@@ -30,6 +30,9 @@ typedef struct pthread_attr_t {
 
 typedef void *pthread_t;
 
+/* Semaphore */
+typedef struct k_sem sem_t;
+
 /* Mutex */
 typedef struct pthread_mutex {
 	struct k_sem *sem;