bits/byteswap-common.h: import recent headers from glibc

On systems where uClibc doesn't provide an arch specific byteswap.h,
we fall back on bits/byteswap-common.h.  However, there is a bug
in this header in the __bswap_constant_64(x) macro.  If, for example,
a double is passed, we get 'invalid operands to binary &' in which we
mismatch a 'double' and 'long long unsigned int'.  The newer glibc
headers fix this and so we import them.  Also, since the inclusion of
byteswap.h is not appropriate for assembly code, we guard a portion
of endian.h which uses byteswap.h from inclusion in any assembly.

This is needed, for example, for f2fs-tools 1.6.0 on 32-bit big
endian PowerPC.

Signed-off-by: Anthony G. Basile <blueness@gentoo.org>

1 files changed, 34 insertions, 0 deletions

diff --git a/libc/sysdeps/linux/common/bits/byteswap-16.h b/libc/sysdeps/linux/common/bits/byteswap-16.h
new file mode 100644
index 000000000..8063aa82d
--- /dev/null
+++ b/libc/sysdeps/linux/common/bits/byteswap-16.h
@@ -0,0 +1,34 @@
+/* Macros to swap the order of bytes in 16-bit integer values.
+   Copyright (C) 2012-2016 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_BYTESWAP_H
+# error "Never use <bits/byteswap-16.h> directly; include <byteswap.h> instead."
+#endif
+
+#ifdef __GNUC__
+# define __bswap_16(x) \
+    (__extension__							      \
+     ({ unsigned short int __bsx = (unsigned short int) (x);		      \
+       __bswap_constant_16 (__bsx); }))
+#else
+static __inline unsigned short int
+__bswap_16 (unsigned short int __bsx)
+{
+  return __bswap_constant_16 (__bsx);
+}
+#endif