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/sys/statvfs.h

@@ -0,0 +1,37 @@
+#ifndef _SYS_STATVFS_H
+#define _SYS_STATVFS_H 1
+
+// https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/sys_statvfs.h.html
+
+#include <sys/cdefs.h>
+
+__BEGIN_DECLS
+
+#define __need_fsblkcnt_t
+#define __need_fsfilcnt_t
+#include <sys/types.h>
+
+struct statvfs
+{
+	unsigned long	f_bsize;	/* File system block size. */
+	unsigned long	f_frsize;	/* Fundamental file system block size. */
+	fsblkcnt_t		f_blocks;	/* Total number of blocks on file system in units of f_frsize. */
+	fsblkcnt_t		f_bfree;	/* Total number of free blocks. */
+	fsblkcnt_t		f_bavail;	/* Number of free blocks available to non-privileged process. */
+	fsfilcnt_t		f_files;	/* Total number of file serial numbers. */
+	fsfilcnt_t		f_ffree;	/* Total number of free file serial numbers. */
+	fsfilcnt_t		f_favail;	/* Number of file serial numbers available to non-privileged process. */
+	unsigned long	f_fsid;		/* File system ID. */
+	unsigned long	f_flag;		/* Bit mask of f_flag values. */
+	unsigned long	f_namemax;	/* Maximum filename length. */
+};
+
+#define ST_RDONLY 0x01
+#define ST_NOSUID 0x02
+
+int fstatvfs(int fildes, struct statvfs* buf);
+int statvfs(const char* __restrict path, struct statvfs* __restrict buf);
+
+__END_DECLS
+
+#endif