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/fcntl.cpp

@@ -0,0 +1,40 @@
+#include <fcntl.h>
+#include <errno.h>
+#include <stdarg.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+int creat(const char* path, mode_t mode)
+{
+	return syscall(SYS_CREATE, path, S_IFREG | mode);
+}
+
+int open(const char* path, int oflag, ...)
+{
+	va_list args;
+	va_start(args, oflag);
+	mode_t mode = va_arg(args, mode_t);
+	va_end(args);
+
+	return syscall(SYS_OPEN, path, oflag, mode);
+}
+
+int openat(int fd, const char* path, int oflag, ...)
+{
+	va_list args;
+	va_start(args, oflag);
+	mode_t mode = va_arg(args, mode_t);
+	va_end(args);
+
+	return syscall(SYS_OPENAT, fd, path, oflag, mode);
+}
+
+int fcntl(int fildes, int cmd, ...)
+{
+	va_list args;
+	va_start(args, cmd);
+	int extra = va_arg(args, int);
+	va_end(args);
+
+	return syscall(SYS_FCNTL, fildes, cmd, extra);
+}