Libraries: Create top level directory for libraries.

Things were getting a little crowded in the project root, so this patch
moves the Lib*/ directories into Libraries/.

Libraries/LibC/dirent.h

@@ -0,0 +1,30 @@
+#pragma once
+
+#include <sys/cdefs.h>
+#include <sys/types.h>
+
+__BEGIN_DECLS
+
+struct dirent {
+    ino_t d_ino;
+    off_t d_off;
+    unsigned short d_reclen;
+    unsigned char d_type;
+    char d_name[256];
+};
+
+struct __DIR {
+    int fd;
+    struct dirent cur_ent;
+    char* buffer;
+    size_t buffer_size;
+    char* nextptr;
+};
+typedef struct __DIR DIR;
+
+DIR* opendir(const char* name);
+int closedir(DIR*);
+struct dirent* readdir(DIR*);
+int dirfd(DIR*);
+
+__END_DECLS