LibC: Add semaphore stubs

These are needed for our bochs port

userspace/libraries/LibC/CMakeLists.txt

@@ -27,6 +27,7 @@ set(LIBC_SOURCES
 	pwd.cpp
 	scanf_impl.cpp
 	sched.cpp
+	semaphore.cpp
 	setjmp.cpp
 	signal.cpp
 	stdio.cpp

userspace/libraries/LibC/semaphore.cpp

@@ -0,0 +1,47 @@
+#include <BAN/Debug.h>
+
+#include <errno.h>
+#include <semaphore.h>
+
+int sem_destroy(sem_t* sem)
+{
+	(void)sem;
+	dwarnln("TODO: sem_destroy");
+	errno = ENOTSUP;
+	return -1;
+}
+
+int sem_init(sem_t* sem, int pshared, unsigned value)
+{
+	(void)sem;
+	(void)pshared;
+	(void)value;
+	dwarnln("TODO: sem_init");
+	errno = ENOTSUP;
+	return -1;
+}
+
+int sem_post(sem_t* sem)
+{
+	(void)sem;
+	dwarnln("TODO: sem_post");
+	errno = ENOTSUP;
+	return -1;
+
+}
+
+int sem_trywait(sem_t* sem)
+{
+	(void)sem;
+	dwarnln("TODO: sem_trywait");
+	errno = ENOTSUP;
+	return -1;
+}
+
+int sem_wait(sem_t* sem)
+{
+	(void)sem;
+	dwarnln("TODO: sem_wait");
+	errno = ENOTSUP;
+	return -1;
+}