Make struct FILE opaque.

Bug: http://b/24807045
Change-Id: I3cb4e436325a65bef3b203e3970e4d967101fcce
diff --git a/libc/include/stdio.h b/libc/include/stdio.h
index c4bfb4f..1df4b54 100644
--- a/libc/include/stdio.h
+++ b/libc/include/stdio.h
@@ -38,14 +38,6 @@
 #ifndef	_STDIO_H_
 #define	_STDIO_H_
 
-/*
- * This file must contain a reference to __gnuc_va_list so that GCC's
- * fixincludes knows that that's what's being used for va_list, and so
- * to leave our <stdio.h> alone. (fixincludes gets in the way of pointing
- * one toolchain at various different sets of platform headers.)
- * If you alter this comment, be sure to keep "__gnuc_va_list" in it!
- */
-
 #include <sys/cdefs.h>
 #include <sys/types.h>
 
@@ -59,94 +51,9 @@
 
 typedef off_t fpos_t;		/* stdio file position type */
 
-/*
- * NB: to fit things in six character monocase externals, the stdio
- * code uses the prefix `__s' for stdio objects, typically followed
- * by a three-character attempt at a mnemonic.
- */
+struct __sFILE;
+typedef struct __sFILE FILE;
 
-/* stdio buffers */
-#if defined(__LP64__)
-struct __sbuf {
-  unsigned char* _base;
-  size_t _size;
-};
-#else
-struct __sbuf {
-	unsigned char *_base;
-	int	_size;
-};
-#endif
-
-/*
- * stdio state variables.
- *
- * The following always hold:
- *
- *	if (_flags&(__SLBF|__SWR)) == (__SLBF|__SWR),
- *		_lbfsize is -_bf._size, else _lbfsize is 0
- *	if _flags&__SRD, _w is 0
- *	if _flags&__SWR, _r is 0
- *
- * This ensures that the getc and putc macros (or inline functions) never
- * try to write or read from a file that is in `read' or `write' mode.
- * (Moreover, they can, and do, automatically switch from read mode to
- * write mode, and back, on "r+" and "w+" files.)
- *
- * _lbfsize is used only to make the inline line-buffered output stream
- * code as compact as possible.
- *
- * _ub, _up, and _ur are used when ungetc() pushes back more characters
- * than fit in the current _bf, or when ungetc() pushes back a character
- * that does not match the previous one in _bf.  When this happens,
- * _ub._base becomes non-nil (i.e., a stream has ungetc() data iff
- * _ub._base!=NULL) and _up and _ur save the current values of _p and _r.
- *
- * NOTE: if you change this structure, you also need to update the
- * std() initializer in findfp.c.
- */
-typedef	struct __sFILE {
-	unsigned char *_p;	/* current position in (some) buffer */
-	int	_r;		/* read space left for getc() */
-	int	_w;		/* write space left for putc() */
-#if defined(__LP64__)
-	int	_flags;		/* flags, below; this FILE is free if 0 */
-	int	_file;		/* fileno, if Unix descriptor, else -1 */
-#else
-	short	_flags;		/* flags, below; this FILE is free if 0 */
-	short	_file;		/* fileno, if Unix descriptor, else -1 */
-#endif
-	struct	__sbuf _bf;	/* the buffer (at least 1 byte, if !NULL) */
-	int	_lbfsize;	/* 0 or -_bf._size, for inline putc */
-
-	/* operations */
-	void	*_cookie;	/* cookie passed to io functions */
-	int	(*_close)(void *);
-	int	(*_read)(void *, char *, int);
-	fpos_t	(*_seek)(void *, fpos_t, int);
-	int	(*_write)(void *, const char *, int);
-
-	/* extension data, to avoid further ABI breakage */
-	struct	__sbuf _ext;
-	/* data for long sequences of ungetc() */
-	unsigned char *_up;	/* saved _p when _p is doing ungetc data */
-	int	_ur;		/* saved _r when _r is counting ungetc data */
-
-	/* tricks to meet minimum requirements even when malloc() fails */
-	unsigned char _ubuf[3];	/* guarantee an ungetc() buffer */
-	unsigned char _nbuf[1];	/* guarantee a getc() buffer */
-
-	/* separate buffer for fgetln() when line crosses buffer boundary */
-	struct	__sbuf _lb;	/* buffer for fgetln() */
-
-	/* Unix stdio files get aligned to block boundaries on fseek() */
-	int	_blksize;	/* stat.st_blksize (may be != _bf._size) */
-	fpos_t	_offset;	/* current lseek offset */
-} FILE;
-
-/* Legacy BSD implementation of stdin/stdout/stderr. */
-extern FILE __sF[];
-/* More obvious implementation. */
 extern FILE* stdin;
 extern FILE* stdout;
 extern FILE* stderr;