diff --git a/libc/stdio/fileext.h b/libc/stdio/fileext.h
deleted file mode 100644
index 6cacc0f..0000000
--- a/libc/stdio/fileext.h
+++ /dev/null
@@ -1,80 +0,0 @@
-/*	$OpenBSD: fileext.h,v 1.2 2005/06/17 20:40:32 espie Exp $	*/
-/* $NetBSD: fileext.h,v 1.5 2003/07/18 21:46:41 nathanw Exp $ */
-
-/*-
- * Copyright (c)2001 Citrus Project,
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- *
- * $Citrus$
- */
-
-#ifndef _FILEEXT_H_
-#define _FILEEXT_H_
-
-#include <pthread.h>
-#include <stdbool.h>
-
-__BEGIN_DECLS
-
-/*
- * file extension
- */
-struct __sfileext {
-	struct	__sbuf _ub;		/* ungetc buffer */
-	struct wchar_io_data _wcio;	/* wide char io status */
-	pthread_mutex_t _lock;		/* file lock */
-	bool _stdio_handles_locking;	/* __fsetlocking support */
-};
-
-#if defined(__cplusplus)
-#define _EXT(fp) reinterpret_cast<__sfileext*>((fp)->_ext._base)
-#else
-#define _EXT(fp) ((struct __sfileext *)((fp)->_ext._base))
-#endif
-
-#define _UB(fp) _EXT(fp)->_ub
-#define _FLOCK(fp)  _EXT(fp)->_lock
-
-#define _FILEEXT_INIT(fp) \
-do { \
-	_UB(fp)._base = NULL; \
-	_UB(fp)._size = 0; \
-	WCIO_INIT(fp); \
-	pthread_mutexattr_t attr; \
-	pthread_mutexattr_init(&attr); \
-	pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE); \
-	pthread_mutex_init(&_FLOCK(fp), &attr); \
-	pthread_mutexattr_destroy(&attr); \
-	_EXT(fp)->_stdio_handles_locking = true; \
-} while (0)
-
-#define _FILEEXT_SETUP(f, fext) \
-do { \
-	(f)->_ext._base = (unsigned char *)(fext); \
-	_FILEEXT_INIT(f); \
-} while (0)
-
-__END_DECLS
-
-#endif /* _FILEEXT_H_ */
diff --git a/libc/stdio/findfp.c b/libc/stdio/findfp.c
index 5e51198..2696cfd 100644
--- a/libc/stdio/findfp.c
+++ b/libc/stdio/findfp.c
@@ -60,15 +60,20 @@
 _THREAD_PRIVATE_MUTEX(__sfp_mutex);
 
 static struct __sfileext __sFext[3];
+
+// __sF is exported for backwards compatibility. Until M, we didn't have symbols
+// for stdin/stdout/stderr; they were macros accessing __sF.
 FILE __sF[3] = {
 	std(__SRD, STDIN_FILENO),		/* stdin */
 	std(__SWR, STDOUT_FILENO),		/* stdout */
 	std(__SWR|__SNBF, STDERR_FILENO)	/* stderr */
 };
+
+struct glue __sglue = { &uglue, 3, __sF };
+
 FILE* stdin = &__sF[0];
 FILE* stdout = &__sF[1];
 FILE* stderr = &__sF[2];
-struct glue __sglue = { &uglue, 3, __sF };
 
 static struct glue *
 moreglue(int n)
diff --git a/libc/stdio/local.h b/libc/stdio/local.h
index ce04141..749de7b 100644
--- a/libc/stdio/local.h
+++ b/libc/stdio/local.h
@@ -32,17 +32,114 @@
  * SUCH DAMAGE.
  */
 
+#ifndef __BIONIC_STDIO_LOCAL_H__
+#define __BIONIC_STDIO_LOCAL_H__
+
+#include <pthread.h>
+#include <stdbool.h>
+#include <wchar.h>
+#include "wcio.h"
+
 /*
  * Information local to this implementation of stdio,
  * in particular, macros and private variables.
  */
 
-#include <wchar.h>
-#include "wcio.h"
-#include "fileext.h"
-
 __BEGIN_DECLS
 
+struct __sbuf {
+  unsigned char* _base;
+#if defined(__LP64__)
+  size_t _size;
+#else
+  int _size;
+#endif
+};
+
+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 extension
+ */
+struct __sfileext {
+  /* ungetc buffer */
+  struct __sbuf _ub;
+
+  /* wide char io status */
+  struct wchar_io_data _wcio;
+
+  /* file lock */
+  pthread_mutex_t _lock;
+
+  /* __fsetlocking support */
+  bool _stdio_handles_locking;
+};
+
+#if defined(__cplusplus)
+#define _EXT(fp) reinterpret_cast<__sfileext*>((fp)->_ext._base)
+#else
+#define _EXT(fp) ((struct __sfileext *)((fp)->_ext._base))
+#endif
+
+#define _UB(fp) _EXT(fp)->_ub
+#define _FLOCK(fp)  _EXT(fp)->_lock
+
+#define _FILEEXT_INIT(fp) \
+do { \
+	_UB(fp)._base = NULL; \
+	_UB(fp)._size = 0; \
+	WCIO_INIT(fp); \
+	pthread_mutexattr_t attr; \
+	pthread_mutexattr_init(&attr); \
+	pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE); \
+	pthread_mutex_init(&_FLOCK(fp), &attr); \
+	pthread_mutexattr_destroy(&attr); \
+	_EXT(fp)->_stdio_handles_locking = true; \
+} while (0)
+
+#define _FILEEXT_SETUP(f, fext) \
+do { \
+	(f)->_ext._base = (unsigned char *)(fext); \
+	_FILEEXT_INIT(f); \
+} while (0)
+
 /*
  * Android <= KitKat had getc/putc macros in <stdio.h> that referred
  * to __srget/__swbuf, so those symbols need to be public for LP32
@@ -143,3 +240,5 @@
 #pragma GCC visibility pop
 
 __END_DECLS
+
+#endif