BuildSystem: Move all userpace libraries under the userspace directory

As the number of libraries is increasing, root directory starts to
expand. This adds better organization for libraries

userspace/libraries/LibC/include/fcntl.h

@@ -0,0 +1,107 @@
+#ifndef _FCNTL_H
+#define _FCNTL_H 1
+
+// https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/fcntl.h.html
+
+#include <sys/cdefs.h>
+
+__BEGIN_DECLS
+
+#include <sys/stat.h>
+#include <unistd.h>
+
+#define __need_mode_t
+#define __need_off_t
+#define __need_pid_t
+#include <sys/types.h>
+
+#define F_DUPFD			1
+#define F_DUPFD_CLOEXEC	2
+#define F_GETFD			3
+#define F_SETFD			4
+#define F_GETFL			5
+#define F_SETFL			6
+#define F_GETLK			7
+#define F_SETLK			8
+#define F_SETLKW		9
+#define F_GETOWN		10
+#define F_SETOWN		11
+
+#define FD_CLOEXEC 1
+
+#define F_RDLCK 1
+#define F_UNLCK 2
+#define F_WRLCK 3
+
+// NOTE: also defined in stdio.h
+#define SEEK_SET 1
+#define SEEK_CUR 2
+#define SEEK_END 3
+
+/* bits 4-11 */
+#define O_CLOEXEC	0x00010
+#define O_CREAT		0x00020
+#define O_DIRECTORY	0x00040
+#define O_EXCL		0x00080
+#define O_NOCTTY	0x00100
+#define O_NOFOLLOW	0x00200
+#define O_TRUNC		0x00400
+#define O_TTY_INIT	0x00800
+
+/* bits 12-16 */
+#define O_APPEND	0x01000
+#define O_DSYNC		0x02000
+#define O_NONBLOCK	0x04000
+#define O_RSYNC		0x08000
+#define O_SYNC		0x10000
+
+/* bits 0-3 */
+#define O_RDONLY	0x00001
+#define O_WRONLY	0x00002
+#define O_RDWR		(O_RDONLY | O_WRONLY)
+#define O_SEARCH	0x00004
+#define O_EXEC		0x00008
+#define O_ACCMODE	0x0000F
+
+/* bit 17 */
+#define AT_FDCWD	0x20000
+
+/* bit 18 */
+#define AT_EACCESS	0x40000
+
+/* bit 19 */
+#define AT_SYMLINK_NOFOLLOW 0x80000
+
+/* bit 20 */
+#define AT_SYMLINK_FOLLOW 0x100000
+
+/* bit 21 */
+#define AT_REMOVEDIR 0x200000
+
+/* bits 22-27 */
+#define POSIX_FADV_DONTNEED		0x0400000
+#define POSIX_FADV_NOREUSE		0x0800000
+#define POSIX_FADV_NORMAL		0x1000000
+#define POSIX_FADV_RANDOM		0x2000000
+#define POSIX_FADV_SEQUENTIAL	0x4000000
+#define POSIX_FADV_WILLNEED		0x8000000
+
+struct flock
+{
+	short l_type;	/* Type of lock; F_RDLCK, F_WRLCK, F_UNLCK. */
+	short l_whence;	/* Flag for starting offset. */
+	off_t l_start;	/* Relative offset in bytes. */
+	off_t l_len;	/* Size; if 0 then until EOF. */
+	pid_t l_pid;	/* Process ID of the process holding the lock; returned with F_GETLK. */
+};
+
+int creat(const char* path, mode_t mode);
+int fcntl(int fildes, int cmd, ...);
+int open(const char* path, int oflag, ...);
+int openat(int fd, const char* path, int oflag, ...);
+int posix_fadvise(int fd, off_t offset, off_t len, int advice);
+int posix_fallocate(int fd, off_t offset, off_t len);
+
+__END_DECLS
+
+#endif