headers: properly decorate attributes

Found by:
find -name '*.h' |xargs grep -i 'attribute.*(([a-z]'

For an example of the type of bugs this causes, try compiling this valid
C11 program (it's valid because 'noreturn' is reserved for use in the
user namespace unless you include <stdnoreturn.h>):

$ cat foo.c
#define noreturn __attribute__((noreturn))
#include <stdlib.h>
$ gcc -c -o foo.o -Wall foo.c
In file included from /usr/include/stdlib.h:11:0,
                 from foo.c:2:
foo.c:1:18: error: expected ')' before '__attribute__'
 #define noreturn __attribute__((noreturn))
                  ^
/usr/include/stdlib.h:66:28: error: expected ',' or ';' before ')' token
 _VOID _EXFUN(abort,(_VOID) _ATTRIBUTE ((noreturn)));
                            ^

* libc/machine/spu/spu_timer_internal.h: Decorate attribute names
with __, for namespace safety.
* libc/machine/xscale/machine/profile.h: Likewise.
* libc/include/stdlib.h: Likewise.
* libc/include/_ansi.h: Likewise.
* libc/include/sys/unistd.h: Likewise.
* libc/sys/linux/linuxthreads/libc-symbols.h: Likewise.
* libc/sys/linux/linuxthreads/internals.h: Likewise.
* libc/sys/linux/machine/i386/weakalias.h: Likewise.
* libc/sys/linux/machine/i386/dl-procinfo.h: Likewise.
* libc/sys/linux/machine/i386/dl-machine.h: Likewise.
* libc/sys/linux/libc-symbols.h: Likewise.
* libc/sys/linux/iconv/gconv_charset.h: Likewise.
* libc/sys/linux/include/resolv.h: Likewise.
* libc/sys/linux/sys/unistd.h: Likewise.
* libc/sys/linux/dl/atomicity.h: Likewise.
* libc/sys/linux/dl/dynamic-link.h: Likewise.
* libc/sys/linux/dl/ldsodefs.h: Likewise.

1 files changed, 2 insertions, 2 deletions

diff --git a/newlib/libc/sys/linux/dl/dynamic-link.h b/newlib/libc/sys/linux/dl/dynamic-link.h
index c1709f7c6..4445bca48 100644
--- a/newlib/libc/sys/linux/dl/dynamic-link.h
+++ b/newlib/libc/sys/linux/dl/dynamic-link.h
@@ -31,12 +31,12 @@
 
 /* Global read-only variable defined in rtld.c which is nonzero if we
    shall give more warning messages.  */
-extern int _dl_verbose __attribute__ ((unused));
+extern int _dl_verbose __attribute__ ((__unused__));
 
 
 /* Read the dynamic section at DYN and fill in INFO with indices DT_*.  */
 
-static void __attribute__ ((unused))
+static void __attribute__ ((__unused__))
 elf_get_dynamic_info (struct link_map *l)
 {
   ElfW(Dyn) *dyn = l->l_ld;