Fix fflush issues.

* libc/stdio/fflush.c (_fflush_r): New function.
(fflush): Fix reentrancy and large offset behavior.
* libc/include/stdio.h (_fflush_r): Add prototype.
* libc/stdio/fclose.c (_fclose_r): All fflush callers changed.
* libc/stdio/freopen.c (_freopen_r): Likewise.
* libc/stdio/fseek.c (_fseek_r): Likewise.
* libc/stdio/ftell.c (_ftell_r): Likewise.
* libc/stdio/fvwrite.c (__sfvwrite_r): Likewise.
* libc/stdio/refill.c (__srefill_r): Likewise.
* libc/stdio/setvbuf.c (setvbuf): Likewise.
* libc/stdio/ungetc.c (_ungetc_r): Likewise.
* libc/stdio/vfprintf.c (__sbprintf): Likewise.
* libc/stdio/wbuf.c (__swbuf_r): Likewise.
* libc/stdio64/freopen64.c (_freopen64_r): Likewise.
* libc/stdio64/fseeko64.c (_fseeko64_r): Likewise.  Defer to
32-bit version if not large file.
* libc/stdio64/ftello64.c (_ftello64_r): Likewise.
* libc/stdio64/tmpfile64.c (_tmpfile64_r): Avoid compile warning.

newlib/libc/stdio64/freopen64.c

@@ -124,7 +124,7 @@ _DEFUN (_freopen64_r, (ptr, file, mode, fp),
   else
     {
       if (fp->_flags & __SWR)
-	 fflush (fp);
+	_fflush_r (ptr, fp);
       /*
        * If close is NULL, closing is a no-op, hence pointless.
        * If file is NULL, the file should not be closed.

newlib/libc/stdio64/fseeko64.c

@@ -111,11 +111,22 @@ _DEFUN (_fseeko64_r, (ptr, fp, offset, whence),
   struct stat64 st;
   int havepos;
 
+  /* Only do 64-bit seek on large file.  */
+  if (!(fp->_flags & __SL64))
+    {
+      if ((_off_t) offset != offset)
+	{
+	  ptr->_errno = EOVERFLOW;
+	  return EOF;
+	}
+      return (_off64_t) _fseeko_r (ptr, fp, offset, whence);
+    }
+
   /* Make sure stdio is set up.  */
 
   CHECK_INIT (ptr, fp);
 
-  _flockfile(fp);
+  _flockfile (fp);
 
   curoff = fp->_offset;
 
@@ -125,12 +136,12 @@ _DEFUN (_fseeko64_r, (ptr, fp, offset, whence),
   if (fp->_flags & __SAPP && fp->_flags & __SWR)
     {
       /* So flush the buffer and seek to the end.  */
-      fflush (fp);
+      _fflush_r (ptr, fp);
     }
 
   /* Have to be able to seek.  */
 
-  if ((seekfn = fp->_seek64) == NULL || !(fp->_flags & __SL64))
+  if ((seekfn = fp->_seek64) == NULL)
     {
       ptr->_errno = ESPIPE;	/* ??? */
       _funlockfile(fp);
@@ -150,7 +161,7 @@ _DEFUN (_fseeko64_r, (ptr, fp, offset, whence),
        * we have to first find the current stream offset a la
        * ftell (see ftell for details).
        */
-      fflush(fp);   /* may adjust seek offset on append stream */
+      _fflush_r (ptr, fp);   /* may adjust seek offset on append stream */
       if (fp->_flags & __SOFF)
 	curoff = fp->_offset;
       else
@@ -323,7 +334,8 @@ _DEFUN (_fseeko64_r, (ptr, fp, offset, whence),
    */
 
 dumb:
-  if (fflush (fp) || seekfn (ptr, fp->_cookie, offset, whence) == POS_ERR)
+  if (_fflush_r (ptr, fp)
+      || seekfn (ptr, fp->_cookie, offset, whence) == POS_ERR)
     {
       _funlockfile(fp);
       return EOF;

newlib/libc/stdio64/ftello64.c

@@ -91,6 +91,10 @@ _DEFUN (_ftello64_r, (ptr, fp),
 {
   _fpos64_t pos;
 
+  /* Only do 64-bit tell on large file.  */
+  if (!(fp->_flags & __SL64))
+    return (_off64_t) _ftello_r (ptr, fp);
+
   /* Ensure stdio is set up.  */
 
   CHECK_INIT (ptr, fp);
@@ -106,7 +110,7 @@ _DEFUN (_ftello64_r, (ptr, fp),
 
   /* Find offset of underlying I/O object, then
      adjust for buffered bytes.  */
-  fflush(fp);           /* may adjust seek offset on append stream */
+  _fflush_r (ptr, fp);           /* may adjust seek offset on append stream */
   if (fp->_flags & __SOFF)
     pos = fp->_offset;
   else

newlib/libc/stdio64/tmpfile64.c

@@ -48,6 +48,7 @@ Supporting OS subroutines required: <<close>>, <<fstat>>, <<getpid>>,
 */
 
 #include <stdio.h>
+#include <reent.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <sys/stat.h>