lib: c: io: implement standard FILE and DIR interfaces

lib/libc/include/dirent.h

@@ -1,6 +1,8 @@
 #ifndef DIRENT_H_
 #define DIRENT_H_
 
+#include <sys/types.h>
+
 #define DT_UNKNOWN 0
 #define DT_BLK     1
 #define DT_CHR     2
@@ -10,4 +12,22 @@
 #define DT_REG     6
 #define DT_SOCK    7
 
+struct dirent {
+	ino_t d_ino;
+	off_t d_off;
+	unsigned short d_reclen;
+	unsigned char d_type;
+	char d_name[256];
+};
+
+struct __opaque_dir;
+typedef struct __opaque_dir DIR;
+
+extern DIR *opendir(const char *name);
+extern DIR *fdopendir(int fd);
+
+extern int closedir(DIR *dirp);
+
+extern struct dirent *readdir(DIR *dirp);
+
 #endif