Remove __need_IOV_MAX and __need_FOPEN_MAX.

__need_FOPEN_MAX wasn't being used anywhere.  __need_IOV_MAX was more
complicated; the basic deal is that sys/uio.h wants to define a
constant named UIO_MAXIOV and bits/xopen_lim.h wants to define a
constant named IOV_MAX, with the same meaning.  For no apparent reason
this was being handled via bits/stdio_lim.h -- stdio.h is NOT supposed
to define IOV_MAX -- and some mess in Makerules.  Also, bits/uio.h on
Linux was being used as a dumping ground for extension functions.

So now we have bits/uio_lim.h, which defines __IOV_MAX.
bits/xopen_lim.h and sys/uio.h use that to define their respective
constants.  We also now have bits/uio-ext.h, which is the official
Proper Home for extensions to sys/uio.h.  bits/uio.h is removed, and
stdio_lim.h doesn't define IOV_MAX at all.

	* bits/uio_lim.h, sysdeps/unix/sysv/linux/bits/uio_lim.h
	* bits/uio-ext.h, sysdeps/unix/sysv/linux/bits/uio-ext.h: New file.
	* bits/uio.h, sysdeps/unix/sysv/linux/bits/uio.h: Delete file.

	* include/bits/xopen_lim.h: Use bits/uio_lim.h to get the value
	for IOV_MAX.
	* misc/Makefile: Install bits/uio-ext.h and bits/uio_lim.h.
	Don't install bits/uio.h.
	* misc/sys/uio.h: Don't include bits/uio.h.  Do include
	bits/types/struct_iovec.h and bits/uio_lim.h.  Set UIO_MAXIOV
	based on __IOV_MAX. Under __USE_GNU, also include bits/uio-ext.h.

	* stdio-common/stdio_lim.h.in: Remove logic for __need_FOPEN_MAX
	and __need_IOV_MAX.  Don't define IOV_MAX at all.
	* Makerules (stdio_lim.h): Remove logic for setting IOV_MAX.

	* sysdeps/unix/sysv/linux/bits/fcntl-linux.h:
	Include bits/types/struct_iovec.h, not bits/uio.h.
	Use __ssize_t, not ssize_t, in function prototypes.
	Don't use hard TAB for double space after period in comments.

2 files changed, 36 insertions, 5 deletions

diff --git a/bits/uio-ext.h b/bits/uio-ext.h
new file mode 100644
index 0000000..cd4039c
--- /dev/null
+++ b/bits/uio-ext.h
@@ -0,0 +1,28 @@
+/* Operating system-specific extensions to sys/uio.h - generic version.
+   Copyright (C) 2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_UIO_EXT_H
+#define _BITS_UIO_EXT_H 1
+
+#ifndef _SYS_UIO_H
+# error "Never include <bits/uio-ext.h> directly; use <sys/uio.h> instead."
+#endif
+
+/* This operating system does not extend sys/uio.h.  */
+
+#endif /* sys/uio_ext.h */
diff --git a/bits/uio.h b/bits/uio_lim.h
index 96a3a71..63afbdc 100644
--- a/bits/uio.h
+++ b/bits/uio_lim.h
@@ -1,4 +1,5 @@
-/* Copyright (C) 1996-2017 Free Software Foundation, Inc.
+/* Implementation limits related to sys/uio.h - generic version.
+   Copyright (C) 2017 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -15,9 +16,11 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#ifndef _SYS_UIO_H
-# error "Never include <bits/uio.h> directly; use <sys/uio.h> instead."
-#endif
+#ifndef _BITS_UIO_LIM_H
+#define _BITS_UIO_LIM_H 1
 
+/* Maximum length of the 'struct iovec' array in a single call to
+   readv or writev.  If there is no limit, the macro is not defined.  */
+#undef __IOV_MAX
 
-#include <bits/types/struct_iovec.h>
+#endif