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/wordexp.h

@@ -0,0 +1,38 @@
+#ifndef _WORDEXP_H
+#define _WORDEXP_H 1
+
+// https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/wordexp.h.html
+
+#include <sys/cdefs.h>
+
+__BEGIN_DECLS
+
+#define __need_size_t
+#include <stddef.h>
+
+typedef struct
+{
+	size_t	we_wordc;	/* Count of words matched by words. */
+	char**	we_wordv;	/* Pointer to list of expanded words. */
+	size_t	we_offs;	/* Slots to reserve at the beginning of we_wordv. */
+} wordexp_t;
+
+#define WRDE_APPEND		0x01
+#define WRDE_DOOFFS		0x02
+#define WRDE_NOCMD		0x04
+#define WRDE_REUSE		0x08
+#define WRDE_SHOWERR	0x10
+#define WRDE_UNDEF		0x20
+
+#define WRDE_BADCHAR	1
+#define WRDE_BADVAL		2
+#define WRDE_CMDSUB		3
+#define WRDE_NOSPACE	4
+#define WRDE_SYNTAX		5
+
+int		wordexp(const char* __restrict words, wordexp_t* __restrict pwordexp, int flags);
+void	wordfree(wordexp_t* pwordexp);
+
+__END_DECLS
+
+#endif