Address clang warning regarding incorrect flag attempting to force non-executable stacks.

tools/gyp/configurations_make.gypi

 # Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 {
   'variables': {
     'dart_debug_optimization_level%': '2',
   },
   'target_defaults': {
     'configurations': {
@@ skipping 11 matching lines @@
           '-Woverloaded-virtual',
           '-g3',
           '-ggdb3',
           # TODO(iposva): Figure out if we need to pass anything else.
           #'-ansi',
           '-fno-rtti',
           '-fno-exceptions',
           # '-fvisibility=hidden',
           # '-fvisibility-inlines-hidden',
           '-fstack-protector',
+          '-Wa,--noexecstack',
         ],
         'ldflags': [
-          '-Wa,--noexecstack',
+          '-Wl,-z,noexecstack',
           '-Wl,-z,now',
           '-Wl,-z,relro',
         ],
       },
 
       'Dart_Linux_ia32_Base': {
         'abstract': 1,
         'cflags': [ '-m32', '-msse2', '-mfpmath=sse' ],
         'ldflags': [ '-m32', ],
         'conditions': [
@@ skipping 193 matching lines @@
           '-O3',
           '-ffunction-sections',
         ],
         'ldflags': [
           '-Wl,--gc-sections',
         ],
       },
     },
   },
 }