Bug#215337: This seems to be rather bad, and probably should be fixed

["Nikita V. Youshchenko" <yoush@cs.msu.su>]

First, this bug is still there in current libc6 from unstable:

nikita@bliss:~> cat t.c
#include <signal.h>

nikita@bliss:~> gcc-2.95 -c -Wall t.c
In file included from /usr/include/asm/sigcontext.h:4,
                 from /usr/include/bits/sigcontext.h:28,
                 from /usr/include/signal.h:326,
                 from t.c:1:
/usr/include/linux/compiler.h:17: warning: `__attribute_used__' redefined
/usr/include/sys/cdefs.h:195: warning: this is the location of the 
previous definition

Second, the symbol in question is defined differently in the mentioned 
places:

/usr/include/sys/cdefs.h, line 195:

# define __attribute_used__ __attribute__ ((__unused__))

/usr/include/linux/compiler:

...
#if !defined(__KERNEL__)
/* Debian: Most of these are inappropriate for userspace.  */
/* We don't define likely, unlikely, or barrier; they're 
namespace-intrusive
   and should not be needed outside of __KERNEL__.  */
# define __attribute_pure__
# define __attribute_used__
# define __deprecated
...

The coment above shows that this point is debian-specific.

Something is broken here.