[RFA] Fix build issue for binutils on newer SunOS systems

["Pierre Muller" <pierre dot muller at ics-cnrs dot unistra dot fr>]

  SUNOS has changed the macro AT_SUN_HWCAP from 2009 to AT_SUN_CAP_HW1.

  This causes a warning, turned into an error by -Werror,
because of re-definition of this macro on a system that
has the new definition of this macro.

  The patch below should avoid getting a warning, both for old and new macro
definition.

  I needed this change to compile 2.26 release successfully, see:
https://sourceware.org/ml/binutils/2016-02/msg00013.html

this was probably due to the missing development mode reset, as stated here:
https://sourceware.org/ml/binutils/2016-01/msg00296.html


I tried to minimize the footprint of the change,
I hope this is the correct way to do it.

Pierre Muller

ChangeLog entry:

        * include/elf/common.h (AT_SUN_HWCAP macro): Undefine if already
defined to avoid
        macro redefinition warning.

--- binutils-2.26-ori/include/elf/common.h      2015-11-13
09:27:42.000000000 +0100
+++ binutils-2.26/include/elf/common.h  2016-02-08 10:10:34.210099916 +0100
@@ -1007,8 +1007,14 @@
#define AT_SUN_LDNAME   2006    /* String giving name of dynamic linker.  */
#define AT_SUN_LPAGESZ  2007    /* Large pagesize.   */
#define AT_SUN_PLATFORM 2008    /* Platform name string.  */
-#define AT_SUN_HWCAP    2009   /* Machine dependent hints about
+#define        AT_SUN_CAP_HW1  2009    /* Machine dependent hints about
                                   processor capabilities.  */
+#ifdef AT_SUN_HWCAP
+#undef AT_SUN_HWCAP            /* Avoid macro redefinition error for SUNOS
host.  */
+#endif
+#define        AT_SUN_HWCAP    AT_SUN_CAP_HW1 /* Deprecated, left for
backward compatibility.  */
+
+/* These are only in kernel */
#define AT_SUN_IFLUSH   2010    /* Should flush icache? */
#define AT_SUN_CPU      2011    /* CPU name string.  */
#define AT_SUN_EMUL_ENTRY 2012 /* COFF entry point address.  */