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.
[Patch, microblaze]: Add config/microblaze.mt for target_makefile_frag

Mirror MIPS method of creating copy of default.mt which drops the
compilation of generic sbrk.c to instead continue using the microblaze
provided version.

[Libgloss]

Changelog

2013-07-15  David Holsgrove <david.holsgrove@xilinx.com>

  * config/microblaze.mt: New file.
  * microblaze/configure.in: Switch default.mt to microblaze.mt.
  * microblaze/configure: Likewise.

Signed-off-by: David Holsgrove <david.holsgrove@xilinx.com>
[Patch, microblaze]: Modified _exceptional_handler

Modified the _exceptional_handler to support
the changes made in GCC related to Superviosry call

Signed-off-by:Nagaraju Mekala<nmekala@xilix.com>
[LOCAL]: Add missing declarations for xil_printf to stdio.h

for inclusion in toolchain and use in c++ apps

Signed-off-by: David Holsgrove <david.holsgrove@xilinx.com>