libiberty/setenv.c: Do not declare environ if defined as a macro.

2015-04-22  Eli Zaretskii  <eliz@gnu.org>

        * strerror.c <sys_nerr, sys_errlist>: Declare only if they aren't
        macros.
        * setenv.c <environ>: Declare only if not a macro.

From-SVN: r222335

libiberty/ChangeLog

+2015-04-22  Eli Zaretskii  <eliz@gnu.org>
+
+	* setenv.c <environ>: Declare only if not a macro.
+
 2015-04-14  Max Ostapenko  <m.ostapenko@partner.samsung.com>
 
 	* testsuite/Makefile.in (LIBCFLAGS): Add LDFLAGS.

libiberty/setenv.c

@@ -63,8 +63,10 @@ extern int errno;
 
 #define __environ	environ
 #ifndef HAVE_ENVIRON_DECL
+#ifndef environ
 extern char **environ;
 #endif
+#endif
 
 #undef setenv
 #undef unsetenv